I found out by chance that my friend is seeing a man who is in a long term relationship and the girlfriend (gf) has no idea.
Background: friend is 20, MM is 20 gf is 19. Friend thinks this makes it excusable, MM and gf been together over 2 years and gf is under the impression they have a solid future together
I don't know MM and gf personally just from what friend has told me.
Friend tells me she doesn't care at all about what happens if gf finds out and doesn't feel bad for what she is doing as she think she is doing nothing wrong
AIBU to be absolutely disgusted and to tell her so? Or shall I keep my own counsel?
(I am not 20 I'm older and married with DCs so maybe have a different view post from friend)