Evebean21,
If you find that anything that helps please let me know. I've been struggling with similar issues. I've been with my boyfriend for a year and a half and have on and off throughout had intrusive/obsessive thoughts that he doesn't love me or he just stays with me because he feels sorry for me. Unfortunately this sometimes leads to thinking that says he's cheating on me but staying in the relationship because he feels sorry for me.
More recently the thoughts have evolved into "Do you really love him? Maybe you're just with him because your scared to be alone?"
I've been dealing with anxiety for over 7 years so while I know that its just anxiety talking sometimes I buy into it. Which makes me feel even more miserable. If you ever want to talk let me know.