That actually sounds like it could be part of PTSD. I felt like that for years because I thought if I got close to someone they would just die. Plus I knew that I couldn't rely on anyone but myself. Especially since the ex is around now. You might be feeling rattled and therefore don't think you can totally trust your bf. even if your conscious thinks you can, your subconscious is damaged from your trauma.

I could e totally off though lol.

I get apathy hardcore during depressed episodes. I'm in an apathetic episode right now. I just don't care. Plus I'm actually a little resentful toward my husband for various things. I hope it goes away.