Mordecaii, what you're feeling doesn't make you disgusting or pathetic. I understand it and I relate to it to a certain extent, because it reminds me of certain feelings / behaviours I had when I was younger. It was a form of insecurity in my case (I had to be the only one because I couldn't bear the thought of someone else's "threat" to take my friend away from me). Unfortunately it doesn't work that way as you know and I had to deal with those feelings once I realized what was behind them and why they were wrong. I would really like to be of more help, but I don't know your story and I wouldn't know how to advise you. Do you have a therapist? Addressing these issues in therapy would be beneficial both to you and your partner.
if ok. Know you're not alone.