Best not ssume only females are unwilling, some men may be too. (side issue but worth noting)
My comment would be that if you can't chat about sex generally (I'm guessing here) then even if she agrees to swing it could lead to problems. Swinging as a couple requires huge honesty and communication. More so than most relationships.
I'm paired with another swinger having met on here - and we still have to work to maintain the communication.