There's a bit of drama in the background to this, but I have a genuine etiquette question so please bear with me!
I'm part of a group that I do a certain activity with every couple of months or so. This group often socialises together outside of this activity, parties etc. There's a weekend long activity (where I'll be there the whole weekend, staying overnight etc) at the end of this month.
A while back (maybe about 2 years) I briefly dated this guy, Mike*, from the activity. We went on 3 dates, but I could tell by the third date I wasn't attracted to him in that way so I broke it off. While we were in that 3 date period he told me about an ex of his and how terrible she'd treated him. This is important later.
Maybe a couple of months later I met my now DH. My DH is not involved in the activity. Shortly after I started getting serious with my DH, Mike asked me to meet up with him at a coffee shop. I agreed with some trepidation. When I arrived at the coffee shop he had a rose and chocolates for me. He told me he was in love with me and wanted me back. It was a very uncomfortable situation. I took him outside (too many people watching us in the coffee shop) and explained that I was involved with someone else and not interested in being in a relationship
with him. I added that I'd like to stay friends. Big mistake...
We tried the friendship thing for a while and things seemed to be going ok, but it always felt a bit uncomfortable. The odd comment here and there. He told me he'd been seeing another girl from the activity and I thought that was great.
Recently I was talking to my sister who is also involved in the activity. She told me that she was talking to the girl that Mike had been seeing. Apparently the girl had a similar story to me. She had gone on a few dates with him, and he had told her he was in love with her. The girl also told my sister that she was not interested in being friends with me because of what Mike had told her about how I treated him. Anyone seeing a pattern here? My sister told the other girl that we had only been on 3 dates, and the girl was very surprised, as though she had been given quite a different impression.
After hearing this I've decided that Mike isn't someone I want as a friend. Unfortunately Mike doesn't seem to feel the same way. He's been sending me txt messages and facebook messages asking to catch up. I've been telling him I'm busy when he asks. I know this isn't the right response but I'm really stumped as to what to tell him.
Does anyone have any ideas how I should tell Mike that I'm not interested in having a friendship with him. I'm nervous because he's very sensitive, and he's also shown that he's not worried about talking about me, and possibly making things up about me, behind my back. I wouldn't be so worried but we will still have to see each other as we're both involved in this activity. The activity will force us to talk and interact at times.