Two-timing

Linda's husband was two-timing her.

My wife used to be a pro-wrestler, so if she ever catches me two-timing her, I'd be beaten to a pulp.

Idiot, I've forgotten that two-timing bitch.

Just wait till I get my hands on that two-timing bastard!

Mary had no reason to suspect that Tom was two-timing her.

I think my boyfriend is two-timing me.

That two-timing SOB really hurt my feelings.

The troubles can be endless: a mix-up on meals, a shortage of liquor, engine difficulties, other mechanical quirks, male pinchers, female whiners, vomiting children, two-timing stewardesses who steal your man, and, once in awhile,^([sic]) a plane that takes a good friend to a fiery death.

His two-timing wrecked his marriage.