My hubby is friends with a lot of my friends too. I don't let him decide who I can friend or not friend. It's not his choice, just like it's not my choice to tell him who his friends can be.
Be friends with whomever you want and don't let it bother you if he gets silly. It's not like you are wanting to go out on dates with any of these old friends anyway.
BTW, I had a really funny experience yesterday. I was checking out a friends "friend list", I have mine hidden but she doesn't. I was looking to see if she was friends with anyone I had not found yet. One of the guys I had a secret crush on at Church, way back in High School, was a friend of hers. I looked at his photos, mine are hidden except for my friends only, he probably had his privacy set for friends of friends to have access, and I looked at one of his profile pictures in his albums and said out loud "Wow, he's a really old man" then I realized...ummm, he's only 6 months older than me. But of course I am NOT an old woman. He just looked like he had been through lifes worst battles and came out alive but showing all the signs of battle.
If your hubby continues to be silly then block him. Change your password. When he tries to access you then you can have a discussion about what agreeable boundaries are. Then if the two of you can agree you can unblock him and friend him again.