tromper
I think my boyfriend is two-timing me.
Je crois que mon copain me trompe.
Is he two-timing?
Est-ce qu'il mène une double vie ?
— Suzume (2022)
She was two-timing that bank clerk for sure.
Elle trompait ce guichetier de banque, c'est certain.
— The Secret in Their Eyes (2009)
So she was two-timing me, huh?
Alors, elle me trompait, hein ?
— Chicago (2002)