invitation

I think you should receive separate invitations if you both know the people getting married or hosting the social event. If only one of you knows the host(s), then its O.K. for that person to receive an invitation with "Bring a guest."

your parents should receive 1 invitation for the two of them and his parents should be receiving 1 invitation for the two of them. You nor your fiance neither one should need an invitation. Usually you would address it to the male or the person you know and their significant other and kids. When you send it to your parents you can address it to the Fathers or I would even just address it to Mr and Mrs John Doe for both sets of parents. Good Luck with the wedding!