Overcoming it? No. Sorry.
With desires like these, I tend to encourage them. This isn’t a matter of your boyfriend being a bad boyfriend. This is about you and you exploring more about yourself. I think you need to take that opportunity. Don’t suppress it. That only makes things worse.
You can either try to make an agreement with your guy that allows you to explore women while still seeing him or you can end it with him and pursue what it is you want. If you want to try being with a woman, the only thing that’s going to solidify your feelings about it one way or the other is actually doing it. Maybe you won’t be that into it, maybe you’ll discover a whole new, untapped passion about yourself that you didnt know existed.
Point is…you have to try. Give yourself the chance to know for sure. It’s not his fault and it’s not yours. That’s just the way life is. “Overcoming” it is not the answer. That’s another way of saying denial. So really think about what it is you want and then go after it.