Evening Lisa,
I'm going to tell you what I'm sure you've already heard 100 times before, it will get better. I say this from experience. My ex-boyfriend and I were madly in love, or so I thought. One of his girlfriends called me to let me know that I wasn't the only one. So, I totally understand what you are talking about. As for why you feel this way ... well, that is because you're hurt and you're still a little stunned. And I'll be honest, it took me a good year and a half to get past thinking about him. And now, if I ever run into him (3 years later) with his new wife, it still feels like a kick in the stomach but it is better.
Just takes time. And until you feel stronger, when you see him and her ... go the other way.
