Sorry, this is long, it's 2:30am and I'm probably rambling!
DP and I have been together almost 10 years, although we broke up for about 6 months, 3 years into the relationship. During this period I became friendly with another, slightly older man. I was late teens and he was almost 30, so not appaling but looking back feel this was quite an age gap considering my age at the time.
It was quite the odd situation - I knew him through work and got on well. He was very full on, quite quickly, in terms of telling people about 'us' (this was never discussed, I though it was just early days!) I was young and initially flattered, but soon got a bit uncomfortable with it all. I saw him and explained it wasn't working after a month or so. He was upset when we had the conversation, but it was dealt with. Carried on working together, bit awkward at first but soon sorted itself out.
Now is when it gets really weird 
After DP and I got back together, he began to get friendly with this man (DP at the time also worked there). They are still friends.
Other man has a girlfriend, who he's been with for some years now. It's been made aware to me that he has told his girlfriend that I was all over him when we were 'seeing' each other and was devastated when we broke up, and from what other friends who know us have said, implied I still like him. This is years after the actual event. So new girlfriend takes an instant dislike to me, along with some other quite nasty things said about me to others. They had an event where DP was invited, but I was clearly told not to come as she didn't want me around. I wasn't prepared to argue about it and didn't kick up a fuss.
We are now getting married, and invites being sorted. DP wanted to invite this friend, which is weird fine. I have however said I don't want her there as I feel it's likely to cause a fuss on the day and I really don't want someone who dislikes me so much at my wedding! Had this been a less important event I wouldn't have minded. I sent a message explaining this (politely!) to friend. He's read the message and received the invite but have had no reply and DP thinks he's annoyed.
I feel like I'm writing a bloody Jeremy Kyle episode - well done if you've made it this far! I'm now thinking let's just say maybe it's best if he doesn't come at all. AIBU?