two-time
To cheat on one's romantic partner (by having a relationship with someone else). After I found out that Jed was two-timing me with the woman next door, I left that lowlife!
two-time someone
Sl. to cheat on or betray one's spouse or lover by dating or seeing someone else. When Mrs. Franklin learned that Mr. Franklin was two-timing her, she left him. Ann told Bob that if he ever two-timed her, she would cause him a lot of trouble.
two-time
tv. to deceive one’s lover. Sam wouldn’t two-time Martha. He just wouldn’t!