SO is turned on by friend having a crush on me? 🤨

So my SO of 7 years has a friend who’s a bit younger than us (I’m 29, his friend is 22, my SO is 31). They hang out a lot and our kids refer to him as uncle. He’s a sweet kid and often jokingly refers to me as his “wife.” He’s always complimenting me and saying he comes around to see me, not my SO. It’s always in a joking way and it’s always in front of my SO so I’ve never felt uncomfortable or weird about it...he just comes off to me as a harmless flirt. And of course it’s nice to get some compliments from a young guy a few months after giving birth 😂

Well this weekend he and my SO were out having drinks and came back to my place after. His friend jumped into bed with me, and my SO was standing at the door and we all just kind of had a chat. It wasn’t anything weird... we just talked about their night. Anyway he left shortly after and my man and I started kissing. Then my SO starts telling me it’s hot that his friend has a thing for me 🤨 I told him he doesn’t, he’s just a flirt and he’s joking around, but my SO said he always says how hot I am. I was just kind of confused as to why my SO would think it’s hot that his friend has a bit of a crush on me. I guess he trusts me and his friend enough that we would never hook up, so to him being with someone that someone else wants is a turn on? I guess I just find it weird cause I wouldn’t feel that way should one of my friends be like that with him lol but I guess that’s just the difference between guys and girls 🤷🏻‍♀️ anyone else’s man like this?