Misericordie,
It’s fine to be close to your family and attached to them. Believe me, I know. I actually moved back home after three years at a big state university and commuted to a local university until I finished my degree, partly because I wasn’t getting a quality education, but more because I was homesick and missed living somewhere that felt like a home. Now I’m married and out of my parents’ house, but we only live about 10 minutes away and I can stop by whenever I want (which is less and less often as DH and I set up our own home).
You need to ask yourself: do I think this is God’s plan for me, to not live my own life but to keep living under my parents’ thumbs? What is the worst thing that will happen if I move out and start my own life? Am I really responsible for my parents’ marriage, or is that between them and God?
Your parents love you and I know you love them, but their happiness and their marriage (however dysfunctional) should not depend on whether or not you live with them and bear the brunt of their problems. Actually, once you move out, you may find that they get along better and that you get along better with them both (this is what happened when I moved out of my parents’ house). You’ll hopefully develop an adult relationship with them, they won’t see you as a child that they still have to raise, and you’ll be able to enjoy your time with them without feeling like you have to be the peace-maker or solve all the problems.
I’m assuming you have the means to move out and into a small house or apartment. Do it. Realize that God takes care of your family as He takes care of you. Their house will not cave in on its foundation if you are not living there. If there are issues in their marriage, those are their issues, and it isn’t right or fair to make you feel responsible. I don’t know if you have a spiritual director or someone else you trust, but if you do you should probably ask them to help you through this. I’ll pray for you. I promise that once you get through the original struggles, starting your own life will be the best thing. God bless and best of luck.
Oh- one other thing. I’m pretty sure you’ve mentioned that you have a younger brother who also has a hard time. If you move into your own place, you will be creating a safe haven for your brother to visit when things at home are difficult. That’s not the only reason to move out, obviously, but it is an added bonus.