I want to watch my husband have sex with someone else

Lately I’ve been fantasizing about my husband having sex with someone(boy or girl, doesn’t matter to me) while I watch. I know he’d be up for it, especially if it’s a girl he does it with, but I’m so afraid it’ll ruin our relationship. I know that I’d love it as it’s happening but maybe I’d resent him later? Idk. Anyone done this with their significant other and everything turn out fine? Was it awkward?