Is there any equivalent for 'amorous affairs' that is very informal?
I'm looking for a way of saying “having amorous affairs”. Ideally it should indicate a married man fooling around with younger women, and the expression should be informal, humorous, in low register but yet not rude.
A short-lived affair is commonly referred to as a fling
Cambridge Dictionaries says
to have a short sexual relationship with someone:
She's been having a fling with her boss.
Consider hanky-panky. It's informal and it's humorous:
informal sexual activity – used humorously
(Longman)
The British down-market term is having a bit on the side