Question

I thought he was my friend, but all the time he was carrying on with my wife!  (UShttps://en.wikipedia.org/wiki/American_English) IPAhttps://en.wiktionary.org/wiki/Wiktionary:International_Phonetic_Alphabet(keyhttps://en.wiktionary.org/wiki/Appendix:English_pronunciation): /ˈkʰæɹijˈɑn/

Accepted Answer

(idiomatichttps://en.wiktionary.org/wiki/Appendix:Glossary#idiomatic) To have an illicithttps://en.wiktionary.org/wiki/illicit sexualhttps://en.wiktionary.org/wiki/sexual relationshiphttps://en.wiktionary.org/wiki/relationship.

Sentence	I thought he was my friend, but all the time he was carrying on with my wife!
Definition	( idiomatic https://en.wiktionary.org/wiki/Appendix:Glossary#idiomatic ) To have an illicit https://en.wiktionary.org/wiki/illicit sexual https://en.wiktionary.org/wiki/sexual relationship https://en.wiktionary.org/wiki/relationship .
Pronunciation	( US https://en.wikipedia.org/wiki/American_English ) IPA https://en.wiktionary.org/wiki/Wiktionary:International_Phonetic_Alphabet ^{(key https://en.wiktionary.org/wiki/Appendix:English_pronunciation )}: /ˈkʰæɹijˈɑn/

I Thought Friend Time Carrying Wife ˈkʰæɹijˈɑn