I'm Not Sure How This is Suposed to Feel

Timm is getting married.
To a girl named Coco.
She used to be a stripper.
She has a kid.
The ring is beautiful.

What do I do about this? Is there some kind of manual about how to deal with this kind of thing? What is the socially accepted protocol for my situation?
I'm not jealous and I don't miss him and I never want to be with him ever again, it just kind of threw my entire day off kilter to see his mug with his bulldog and his Coco. To think that a year ago he was begging me to drive home every weekend and we were fighting about how I was scared to get married and I didn't want to yet (or ever to him) and I was falling for another guy and I wanted out of that relationship so badly but was so scared to hurt anyone. Does this happen all the time? Do people always have to deal with their ex's getting married and just never talk about it? I think I'm finally to the point where I have forgiven Timm for every misdoing he's done to me and I've forgotten how miserable I was with him. I cried about him getting married. I should be happy for him. I don't know why this makes me cry. I'm just very caught off guard and weirded out.
Then come the "what if's": what if he wants me to be in the wedding? what if he invites me to the wedding? what if his crazy family is there? what if people ask me questions? what if she has my wedding?
It's just weird to think about how someone was a part of your life for so long and you were in love, no matter how awful things got and in such a short period of time, everything can be gone. You get over them, they get over you, you move on and you fall in love with someone better. People leave imprints on your life that you cannot erase no matter how painful they are. I wish I could be truly happy for him without crying for some mysterious reason, but I don't think that's possible.
Why does people getting married and having babies bother me so much? It irks me to my very core. I was rifling through my friends status updates on facebook and saw at least four girls with names I didn't recognize and then realized they had gotten married since I'd last seen them. I'm thinking that I'm jealous, even though I'm not to that point in my life at all yet. I want to be married. I want to have children. All some day. College carries so much uncertainty along for the ride. I long for the day I can be established and have a place to park my car without getting a parking ticket.