I've just started experiencing this. It's blown my mind but I don't know why. I think I should have expected it.
I was talking to the father of a former classmate if my chimd's. We'd had some chats years ago when we were both at the park while the kids played. Nothing that interesting, just small talk.
Bumped into him recently in a shop. Normal small talk. He mentioned my husband. I told him he's my ex. This guy switched his behaviour SO fast. He kind of leapt over beside me, started putting his hand on my shoulder. Telling me I looked good (I didn't, objectively I looked dishevelled cos I'd nipped out for a few things in the evening), wanting me to come to some event, finding my number from old Whatsapps for kids' parties years ago and messaging me. He's in a long term (10+ years) relationship with the mother of his second child.
I was not leading him on, not even subconsciously as I got out of an abusive relationship and don't ever want a man in my life again! It was so fast too, there wasn't even time for me to lead him on!
Honestly, I've never seen the change SO blatant. I've thought I've seen it just not like that.
In general, have you noticed men treating you differently when they find out you're divorced?