That's a really sad predicament. I'm truly sorry. I don't know exactly how you've framed things when speaking with your partner, but I think that if you can find the will to consider ending it & moving on then you should have the will to lay everything out- what you want, how they make you feel, how you feel about them and (if you do) why you want your life together to be better. It's probably hard to not make it seem like you're putting them on trial, so make sure that you're willing to be accountable for yourself, too. I'm sure it's in every single advice column, but you could suggest couples counseling- if they refuse then you kind of know your answer as far as how much work they're willing to do.