If you're an amateur like me, the main thing about being in a band is that it's got to be fun. You might get a bit of petrol money at the end of the night from a pub gig, but if you're not making enough to live on, then your enjoyment and satisfaction is the only thing that's important.
There's always going to have to be some give and take when you're in a band, but if all you ever do is give, and all everyone else does is take, that's not a compromise - that's called taking the p1ss.
I've just left a similar situation. I'd stuck with them for over a year, but finally realised that all I ever got from them was lip-service.
In hindsight, I should have been more concerned when I joined about all of their tales of woe about their long list of bass players who were forever leaving and letting them down. Unfortunately the egos involved are so large, and their self awareness so small, that I doubt that they'll ever realise that it's them who are the common denominator.
I had a jam the other day with friends that I hadn't seen for years. It made me realise that I knew guitarists, drummers, singers even! , who were also lovely people. Just because you want to be in a band, it doesn't mean you have to be in a band with a load of a55holes.
Life is short. If you're not having fun, walk.