Me and my girlfriend are having some issues. We are very happy together and we wish to remain together. I’ve considered myself to be a non-monogamist for a long time now. My desire to have sexual but non-romantic relations with other girls makes her uncomfortable. I want to make her more comfortable but she is not very adamant about the idea of her giving it a shot as it goes against her morals what she believes is right. I’ve been very welcoming with her and her issues regarding addiction to substances that I have grown-up believing is very wrong. Over time I have adjusted to this and she feels bad about not being able to adjust to what I desire to do. In order to make my girlfriend more comfortable I wish to somehow solve these feelings and perhaps learn how to redirect them to my girlfriend to invoke an even more passionate relationship. What should I really do?
I think what you both should do — or more to the point, the only sound thing I think you can do — is accept each of your feelings and wants instead of trying to change them. I also think it's important you let your girlfriend know that she should work to accept her feelings as well. I think it would be good if you do what you can to affirm that she does not need to change since it sounds like she may have gotten the idea from you that she should try and change how she feels. Long story short, I think you're both going to be best-served by accepting who each of you are and what you each want, that some of those things are different, and figure out the best way to be in relationship to each other that honors those differences and allows for them, rather than forcing anyone into doing anything they don't want to do, or agreeing to anything they don't want to agree to.
It sounds like you feel you're simply a nonmonogamous person, and that nonmonogamy is what you want. It also sounds like she simply feels that is not for her and that it is not what she wants. Further still, it stands counter to her own values.
Before I move forward, there's something else I want to nip in the bud straightaway. It sounds like you're saying she currently has or has had a substance dependency issue, and you feel you have handled or accepted this in a way which was challenging to you, and counter to the way you were raised, but where you feel you've done a good job. It also sounds like you or she are suggesting that because of that, she should be both able and willing to change her values, identity , feelings and beliefs about nonmonoagmy. If I have that right, I don't see, at all, what one of those things has to do with another. And if this is at all an idea in the mix — I can't tell if it is, but just in case — I certainly don't think she owes you trying nonmonogamy because how you've responded to her dependency issues. I'm sad to hear that it sounds like she has the idea she owes you this because of that, and I find that very troubling.
Here's the thing: you want nonmonogamy. That's a perfectly valid thing to want. There's nothing wrong with you wanting that. She wants monogamy, which is also a perfectly valid thing to want. There's nothing wrong with her wanting that. But those are wants at odds with each other: you want conflicting things.
That leaves you with two basic options: one of you agrees to do something big you don't want to, and may even be in conflict with something as huge as your essential personal values or your identity. Or, you can change the nature of your relationship so that you both get to seek out what you want in this kind of relationship with others whose wants and values are in alignment with yours, and create a relationship that works for you without anyone having to do something big they don't want to do.
I strongly suggest the latter. It sounds like you've already been doing the former with you doing what you don't want, and that you both may have been trying to flip the script so she becomes the one doing something she doesn't want. I don't think that's the way to go, at all, and you already know that just doesn't work.
If you're going to go with the option I'm a fan of, I suggest you start by just having a few long talks where you just dig into what parts of your relationship really seem to work for you. What parts feel like a real fit? What parts, or ways of being together, leave you both feeling like your needs are being met, and like you're only doing what feels right for you? You say you're happy together: if you can clearly identify in what ways you make one another happy and experience happineess together, and also sort out ways that you aren't, you can use all of that to figure out what kind of relationship works for you. That could be shifting to an intimate (emotionally, since it sounds like if you're also with others sexually, she probably won't be okay with sexual intimacy with you) friendship. If you live together and enjoy that, that could be a domestic partnership that isn't sexual. Or maybe, even though you love one another, you're at a time in life where it might actually be best to have a separation for a while so you can each better sort out what you really want and need, and each focus on yourselves for a while instead of each other. Separations can be loving, caring, amicable and positive: they don't have to be tragic or strained.
I want to add a little something extra here. I'm not clear on what the nature of the substance abuse or dependency involved is, both in terms of what it's really about — does your girlfriend have a pain condition or other disability, for instance, or is this recreational; is she currently abusing drugs, or is she in recovery? — or what your involvement has been like. But I do know that you aren't obligated to be with an addict if you don't want to be with an addict, or help someone in their recovery if you don't want to or if it asks things of you you don't want to give. It can be a good thing to ditch certain ideas we grew up with or values we were raised with. It can also be something that isn't good, whether that's because those are our wanted, felt values and we feel they benefit our lives and others or because what's being asked of us is simply problematic (like enabling someone engaging in some kind of abuse).
I'm sorry if whatever has gone down here in this respect wasn't something that you wanted — or isn't still — but that you did anyway. That doesn't mean she owes you the same, like I said, but it also doesn't mean you have to just suck this situation up or keep doing things you don't want to do or aren't okay with. If any of this has been or remains problematic for you, or troubling, or like something you really don't want, I hope that you will address it and make what changes you can so that you're honoring your own wants, values and limits. If you don't already know about them, one avenue of support and help for you in any of this can be al-anon or nar-anon groups or meetings for friends and loved ones of those with substance abuse disorders. If you are concerned that some of why you want to stay together is about codependence, which it probably is if any kind of addiction is in the mix, that's something those kinds of groups can help you sort out and start to change, or consider as you make choices about this relationship.
I'm not sure I understand what you mean when you ask about "solving" your feelings, but if you mean your desire for non-monomgamy, please know that's not something wrong with you that needs fixing. It's something you want that it is okay to want, it just isn't something your current girlfriend also wants. The problem isn't what you want (nor what she does): the problem is that you two want different things, and the setup so far is that one of you has to not get what you want. I don't think the solution is to somehow change yourself or to subjugate or try and redirect your wants; that won't likely work and it also doesn't really respect and affirm who it sounds like you just are. The solution is to find a kind of relationship — with her and with others — where both your wants and needs are aligned.
It's probably going to take a handful of talks and some real time to figure this out. Some of those talks are probably also going to be difficult or painful. But so long as you both really do want to sort out how to be together in a way that does work for you both, and those talks are productive and feel interpersonally and personally beneficial and safe, I'd encourage you to stick it out. You both may find this article, this piece, or this one helpful to read and incorporate parts of in these talks.
What you eventually come to may still feel like a loss at first, particularly if what you decide is to change your sexual or romantic relationship into something that's not sexual or romantic. But if you're both better able to be together without either of you feeling like you're giving anything major up, and both better able to accept the ways you're different instead of struggling with them, in the long run, you're both probably going to be a lot happier, feel a lot better, and also be able to love one another more fully. I wish both of you the very best in this, in your relationship as a whole, and to you as you move forward, hopefully with both of you feeling able to and supported in seeking out what you each truly want.