When it comes to sex and having fun, all married couples are different. Its not right to judge them before you meet and talk to them and see how they feel about a non monogamous marriage.
My gf confessed shed been cheating on me with her ex because she missed his much larger 9 inch cock im 6 inches and was told i was big believed it until i saw my gfs ex bfs 9 inch cock and we took turns fuckin her i was basically a place holder and she felt bad for me so she now lets me have a turn when therr done