Hi GeekyGirl - thanks for your insight and support.
I have been thinking about your question "why does his busy social life make me feel like something is wrong with me?" all day.
Just being asked this question already makes me feel a bit better

- meaning that it points out to me how unrelated the two things really are. However - I have struggled with this type of reaction all my life - to friends getting together (without me), hearing about other people's social lives, etc.
Some thoughts come to mind as to why:
1. My mom would frequently tell me when my friends didn't stop by the house or call on me, that they must not want to be my friend anymore. Or she'd ask me what I did to upset them. That happened frequently enough that it's pretty ingrained - if I'm not included, I've done something wrong.
2. His busy social life was a problem in our r/s - in part because of my issue, although moreso because he uses distraction in a big way to prevent himself from getting close and vulnerable. I would literally not see him for days on end except whenever he would come to bed. He loved this schedule - but as you can imagine, it was a point of contention at times. I guess it still triggers me because I'm hoping somewhere inside that he'll change, consider his own pain, get the help he needs, and come back.
3. I am insecure? Hearing about his busy social life and watching him engage so enthusiastically with others reflects back to me that I'm in a sad place, not having that much fun all the time, and probably a bit more of a downer than I want to be. Although when I'm feeling down, I think I evaluate myself too hard as well.
This has been such a big issue for me all my life- very difficult for me to understand or talk about because I feel shame around it because it doesn't make sense and yet triggers strong feelings. I'm so grateful for the anonymity of this board! And the incredible insight and questions that people ask. Thank-you