I wish to say something along the lines of
"after she found out her husband was cheating on her"
however I have realized that 'cheating' is colloquial. Is there a formal alternative that is a verb?
: to make a cuckold of (a husband)
Philander Main Entry:2philander Function:intransitive verb Inflected Form:philandered ; philandered ; philandering -d()ri\ ; philanders
: to make love frivolously or in a trifling or fickle way : DALLY, FLIRT belles and beaux philandered in the big hotels— Van Wyck Brooks *his penchant for philandering with pretty stenographers finally drove his wife to sue for divorce*
Commit adultery describes the act, but, if you want something less formal, you can use be unfaithful to.
"after she found out her husband was an adulterer"
"after she found out her husband had committed adultery"