You've been conditioned to feel the way you do. He introduced her to your present relationship and she is past. I would suggest couples therapy to work on self esteem and better ways to disagree. You are worth something so much more than being a stand in and he likely realized that but he'd already given you a complex. It's best to get help with the aftermath if you plan to continue on. Do not fret about mental problems, this is a normal stress response and your anguish is more than likely situational and therefore temporary.

Sent using Tapatalk