" The logical part of me says to just end it, to get her and everybody out of my house and my life ASAP. "
This is the best way in your sitch. You're not married after all and she was married twice before. She hasn't learned anything from her previous relationships that you don't switch partners because you're unhappy for a time.
" to take responsibility for the wrongs I committed in the past few months, and make the changes necessary to save the R."
Correct me if I'm wrong but she was plenty wrong also correct? And she continues to treat you like crap even though you allowed her family to come in to live with you. In your case, being a doormat isn't going to work because there's no commitment holding you two together.
I mean is there anything that the two of you share? Bank accounts, mortgage, etc.?
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.