I agree with Raz's post.
It isn't okay for someone to seek out a sexual relationship when in a committed relationship. (imho).
I think there are times in some relationships when cheating does happen, and it may happen for a more valid reason than some. Hopefully when that does happen the couple is able to get by it and still have a strong relationship.
However...if one cheats in a relationship and has no problems in doing so, nor any care to fix or end the current marriage or committed relationship then I agree with Bambina. As for children, that is just more of a reason to work harder with the partner to fix things...not to run away. And as for the men and women that cheat out of purely selfish reasons that have children and a spouse to think of...ugh. THOSE are the people that deserve to be called slime.
A close family friend of mine was in that situation with four children and her husband stepped out of the marriage - ongoing for two years. When she finally 'caught' him she said she wanted to work on the marriage, they went to counseling...but he wouldn't stop. That isn't a decent man. Do I have compassion for him? No. Do I feel bad for not feeling compassion for him? Absolutely not. He ripped those kids lives apart, not to mention his wife's.
And here's another kicker. The other woman was married with five children.
Nice couple of people right?