I've been through this a couple of times. First, ask yourself what you REALLY owe them (financially, personally, etc.) then ask what you owe yourself.

You began your post by saying that things have soured personally, so you might just want to leave outright.

In 1992 I left a band right as we were about to start our first tour in support of our new CD. I thought I was leaving them high and dry (but the problems had become more than I could bear), but got a lesson in humility when they hired a guy every bit as good (if not better) than me wihin a week. HA!!

It's just like Charles DeGaulle said, "The graveyards are full of indispensable people"

What I'm reading in your post is that you're going to go anyway and want somebody to tell you it's OK.

Alright. I'll be the one. Leave them. It's OK. Best of luck.