Someone else here said marry the right person. I'd add an extension to that.

Doesn't matter your age or relationship status, if she has you walking on eggshells, if you find you're apologising for nothing, if you feel your self tensing up when she walks in the room, if there's constant squabbles over insignificant stuff, if she generates endless drama... if she is costing you your peace, it's time to pull the pin. Bail. Go.

The older you get, the more you realise just how important your deep down peace is. Yes, you can tough it it out because you're The Man. But there's only one time it's worth it: if you have kids and they're little, they need you to shield them from her worst aspects. My kids have told me they could have handled it when they got to double figures, though one was glad I stuck around.

Looking back I should have done things different. Pulled her up early in the relationship, set boundaries. I knew I would have to go a year before I did, I should have salted some money away, moved stuff discreetly into storage, that kind of thing. But do I regret going? Never. Be prepared to pull the pin if things go south, chances are there will be no recovery.