Just wanted to hear others opinions about this, as I'm not sure if I'm being unreasonable!! Please be kind, I'm struggling with a baby who won't sleep and I'm all over the place at the moment! 
So... I've become friends with a lady as our children are very close, she's so lovely and we've been arranging to meet up with our partners and kids. I always knew that this lady and my OH went to school together and "hung out" as a group of friends. This is why we have some common ground as we chat about stuff from when my OH was younger. (I didn't grow up in the same area as my other half)
I've been with my OH for 10 years now, and we had a conversation the other day as he's going on a stag do, about this lady and one of the guys and he said "the stag has probably shgged her when they were younger" we laughed it off and I said lightheartedly, "haha, you've not shgged her have ya
"
He went quiet and then said yes, I was still laughing thinking he was joking around, but he wasn't, I shrugged it off as it's not really any of my business, they were kids, we are in our thirties now. Anyway, I've reflected on it, and I do feel a little bit disrespected, I know 100% hands down if he became pally with somebody I'd ever slept with, out of respect I would just want to tell him, in case it ever came up, I wouldn't want him to feel like shit.
I genuinely don't care who he's slept with in his younger years before me. I'm not a jealous person at all, and I still want to be friends with this lady, however, what I do care about is him not respecting me enough to tell me, when I've been rambling on about this lady and arranging days out. I thought I knew everything about him with it being 10 years and 2 kids down the line.
Please can I have your thoughts?
Thanks so much 