There's this train of thought that goes... Men always want to have sex with any woman, therefore, your friend wants to have sex with you, therefore you aren't actually friends, therefore you shouldn't be around him...

But if it's actually true that you need to stay away from men who want to have sex with you (and that's ALL men, except maybe relatives and gay men), that doesn't just mean you can't have male friends. It means you can't have a job with male coworkers, can't go to the store and interact with a male checkout clerk, etc.

In fact, if it's really true that men are always willing to have sex with women they know, then that presumably applies to your husband as well, which would mean the only reason he doesn't cheat on you a dozen times everyday is that the women he encounters don't give him the opportunity. So hopefully he's not actually using this theory as an argument.