Sounds like he is an I'm mature one, just trying to piss you off. Does he have several children with several baby Mama's? I've seen that happen way to much! I'm sorry sweetie, good luck!

Sounds like a bullet dodged.

Wow. OP, keep your head high - my best guess is he's rushing into this, the invitation is clearly sent out just to agitate you. But it's him who will be married to a person he's most likely just with out of spite, not you. Can you RSVP to his new girl? Because I'd be curious if she's aware of the invitation - either she doesn't, or she's in with him on that rather childish plan to get under your skin. Either way, turn around and don't look back. Whatever mess they're getting themselves into, it's gonna be their mess. Take care of yourself.

Either he was a cheating or he rebounded like a rubber ball.

He moved on pretty quickly, or he already dating someone while y'all was together.

Sounds to me like you dodged a bullet! You got to miss years of mental health problems!

Was it a bad breakup? Or a mutual parting of ways? If the first, just maturely RSVP that you wont be attending and leave it at that. If it's the second, just RSVP and leave it at that. I really dont get why this is an FML unless you're not over him (or her).

If they’ll cheat with you, they’ll cheat on you!

So tell me... why didn't you want to get married? Another "half story" where the "poor" OP seems like the victim. Clearly he was ready to take it to the next level and didn't want to **** around, but you had other plans and he got tired of waiting.