do sometimes married women or women in relationships form and 'maintain' 'friendships' with guys in attempt to monkey branch one day eventually for months or years when they already have the husband or boyfriend but nothing ever comes out of it and they end up never moneky branching with the 'guyfriend'?

i ask this because ive had married women seriously flirt with me like wanting me to make a move but they were in married relationships. like they have the plausibility to say it was 'just a friendship' if they decide to back out or change their mind.