Are you not interested in your boyfriend at all? (like are you bisexual, a lesbian, ???) If that's the case, you owe it to him to at least break it off. No one wants to be putting in effort for a relationship where they're not wanted.
I'm proud of you for figuring out you like women, though. It can be a scary road for some, and it sucks that you're in a relationship already, but messy situations are a part of life I suppose.