When you ultimately make that decision to be with one person forever, you are signing up for not only their love, but their trials and vices. You are consenting to help them through the things that they previously had a hard time getting through on their own. As I've begun to go down the road of progressing with my relationships, I am finding out what trials I am willing to sign up for. I don't need to allow myself to suffer the consequences of decisions that I haven't made.
The Atonement encompasses everyone and the power to change is real. Admittedly, more real to me right now is my power to choose what I want to take on from my partner.