There was one relationship I've been concerned about at the emotional level, however I really don't think anything is going on. She obviously hasn't admitted to anything like that.

One of our problems is that we've never really been able to discuss our relationship mainly (IMO) because she gets too defensive and starts reading personal judgments into things. Typically anytime we get into something that matters to me, she'll shut it down with something along the lines of "I know, I'm terrible/horrible/awful..." at which point I remind her she's obviously not. She could easily be depressed.