I had this happen to me in my 30’s. (Sorta.)

Polyamory - a woman who hadn’t been taking on new partners started dating me. My other girlfriend’s husband began awkwardly pursuing her with no grace or finesse. It got awkward. An acquaintance learned that I was dating the second woman (who had also only recently gotten back into the scene), and began pursuing her.

It’s like some guys think that because a woman is available to one (well, two or three), she’s available to all. It felt very much like blood in the water to a shark.