If you're that bored with having sex only with her, then do what most married men and women do; cheat, or get a divorce. Or you could have stayed single and had 3-somes without the adultry part. BTW, see you hell.
Personally, i dont think i would want to see my man getting it in the ass by another guy.....or the other way around......but BEFORE i would even think about letting him lick another girl with me around, THAT would have to happen first
and saying this, now he knows that he will never get a 3some with me and another female