Menage a trois and Romantic affair

Menage a trois noun - Household for three; an arrangement where a married couple and a lover of one of them live together while sharing sexual relations.

Romantic affair and menage a trois are semantically related. In some cases you can use "Romantic affair" instead a noun phrase "Menage a trois".

Menage a trois and romantic affair are semantically related. You can use "Menage a trois" instead a noun phrase "Romantic affair".