Husband left but not entirely sure why!

I really need some advice. I was with my husband for 25 years, since I was 16. Married for 17 of them and we have 3 kids who are all older now. Anyway, 8 months ago he left after a minor argument. When we sat down to talk he said he hadn't been happy for months. I had no idea he was feeling like this, I thought we were happy. We'd booked a holiday 6 weeks before and were awaiting the birth of our first grandchild. When he was pushed for a reason on why he was leaving he said it was because I wasn't affectionate enough! I truly thought revolving my whole life around him was enough. I've always been the type of person who doesn't really show emotion and bottles things up. It used to be a standing joke between us so I dont understand why its a problem now. Our sex life was good I just wasn't all over him in public! Because we got together so young and had the kids early I basically cut myself off from all my friends. I didn't really socialise that much over the past few years because I don't drink and have struggled since my dad died. So the mutual friends we had have stuck with him. I'm now wary when I go out in case I bump into to them because I don't know what he's told everyone because in my eyes the reason he's given me is frankly pathetic! I've accepted he's left and isn't coming back, to be honest I wouldn't take him back anyway. My problem is I can't settle not knowing what he's told everyone. I'm pretty sure there was no one else involved. I'm considering texting one of the mutual friends to ask to meet them to see if I can get any answers. The thing is the only one I'd ask is a guy who was friends with my husband before I met him but this guy was also my first serious boyfriend. And although now a mutual friend I haven't had a real conversation with him in years because my husband got jealous and very moody if I spoke to him. I've been trying to just 'bump into' the guy but had no luck so far. Should I try and speak to him and ask him not to tell anyone or do I need to let the whole thing go and try and get on with my life not knowing??? Any advice greatly appreciated!

Was he a virgin before you got together?

No, few years older than me and he'd had 2 previous pretty serious relationships.