When you truly detach, do these mood swings go away?
I think it totally depends on the individual. Every situation is a little different and people are unique. It's been 2 years since BD for me and I'm still not detached, but W and I still live together and sleep in the same bad, so it's difficult.
That said, it does get a little easier every day. I still feel sad sometimes, or lonely, but I don't spend a lot of time there. It comes, I acknowledge it, and I move on with my day.
Focus on you and the things you can control and hang in there.