Never did well with ultimatums - to me it's an invitation to call their bluff each and every time just out of principle alone.
I am of the personal belief that couples need time together AND time apart doing something for themselves. I'm in the middle of a divorce but the one thing we did do was give each other the time we needed to be with our friends or by ourselves. I never found a reason to be jealous if he wanted a weekend away or to go out with the guys. He played poker with his buddies on a regular basis and I was happy he got a chance to hang with the guys - made him happier. He felt the same for me. Going out on a girls or guys weekend is very different than being with your partner. Both are great, both are needed in mho.
Regarding divorce - it sucks no matter how you look at it. In my case, I'm the one who came in with money and a great career. He came in with nothing but debt. I owned my first house at 24 and had owned three of them by myself before I got married. I leave this marriage minus my career (having gave it up to stay home with our children, a joint decision, for the last 8 years), savings spent to supplement his income when I stopped working, and equity in the house down $100k. For the first time since I was 24 I cannot buy my own home and have almost no money left. He gets half of my equity (Prenups are worthless if they go missing btw, funny how that happens...check your local laws, lawyers only have to keep copies 6 years where mine was drawn up). YET, the divorce is worth it to live happily as opposed to unhappily. If I didn't have children to support I'd not even worry about losing everything to start over.
Do what you have to do to be happy - either work on your marriage to make it better or leave and start a new and happy life for yourself. Just don't do nothing - it makes for a miserable existence. Best wishes to you.