Old boyfriend

I bumped into an old boyfriend that I hadn't seen for about 30 years. We only had a moment to chat but as we are both on Facebook, I said I would message him to catch up. I told my husband but he wasn't very happy about it, I'm in touch with other male colleagues, friends etc but he feels this is different as it's an old boyfriend. I thought that as it was so long ago and the "boy" is in his 70's now, it wasn't a problem. What do others think?