Total deal breaker and I''m speaking from my own experience. Ex-husband cheated while I was pregnant with our third child. We made an attempt to stay together. . . but for me, the cheating was an "unmasking" of sorts. I couldn''t look at him the same loving way. When I looked at him, I was totally repulsed. I was even more repulsed when he tried to touch me. As far as I am concerned, he cheated on me, our kids and our family unit. Marriage requires trust and I did not want to live a lie. I have no regrets.