I don't know why you will have to stay in the marriage for 4 more years but I honestly think that you should get a fresh start right away when you are ready and don't want to stay. Do you want to share the reason why you don't have a choice but to stay in this relationship for 4 more years?
Even if you can't move out now, make your mind think like that. Take this 4 years time to work on yourself, plan perfectly for your future and be emotionally free and independent. All the best!

I feel similarly to you. I was hoping to stay another 4-5 years but I've gotten to the point where every day is a struggle. I do my best to avoid him but it's so hard. I'm looking at going back to therapy but there's no way he'll come. One of the many reasons I want to leave.

I would say look for work that require you to travel might helps. It helps me:)
Or if you want to go out of town, maybe work for local grocery company like instacart. Shop and then deliver. Take off some of my pan s d frustration being home while making extra cash.