cheat on, cheat, cuckold, betray, wander

be sexually unfaithful to one's partner in marriage; "She cheats on her husband"; "Might her husband be wandering?"

• twotime — carry on a romantic relationship with two people at the same time
• play around, fool around — commit adultery

• deceive, lead on, delude, cozen — be false to; be dishonest with