My position may be somewhat unusual, I don't know, but I do know this: My health improved, my mood improved, and my sex life definitely improved when I finally made the choice to become single.
From 1980 to 2003 I was always in a relationship (four all together, one at a time). I never made time to find out what it was like to live successfully on my own. I was too scared, I think. I thought I couldn't live without a relationship.
Unfortunately, I don't have a very good partner-picker. I chose partners who were not all that good for me and who were unlikely to change. Not a happy combination. Lucky for me there is a Twelve Step program for magical thinking.
All those years I spent orbiting other people's lives took a toll on me, emotionally and physically. When I finally allowed myself to claim my independence in 2003, I made a promise to myself that I would never again allow someone else to invade my mental and physical space without my permission.