Friend had affair

[PickledPickles]

More of a WWYD I suppose.

It was on he cards for ages and I made my opinion very clear that I did not approve, that it would harm her relationship with her long term partner of about 20 years and affect the children. She did it anyway and is now committed to her long standing relationship now that she's got it out of her system and essentially had a good shag. It's was kind of one night stand but was planned and she'd done the same before with this man a few years back.
I can't abide infidelity. I was cheated on and it rocked me to the core.
I can't look her or her partner in the eye anymore knowing what I know. I can't see how I can remain friends with someone e who's values are so far from my own.

You're just going to have to cool it off and phase it out if you feel that strongly.

You can’t. You know how you felt when you were cheated on and you’ll feel dishonest every time you see them together. Sad, and shame you’ll lose them as friends. She but did this to your friendship by telling you something you can’t now unknow so it’s on her.

Its nothing to do with you. Tell your friend, "not to tell you anything about it otherwise you'll tell if her husband asks about it".

Take a step back and cool it off with her.

She knows you strongly disapproved. She then had the affair and continued to tell you all about it.

What does she expect? Ignoring she's a shit for being a cheat, she's not very respectful of your friendship, to know you feel strongly against this behaviour, but to "fill you in with all the details" regardless.

Tell her that sadly, you are far less comfortable with her infidelity than she obviously is, and that you will not lie to her DH, so she'd better hope he never asks.

Yes, I'd rather she'd kept it quiet. Now I know and as pp pointed out, I can't un-know.
I don't think it will have got it out of her system either. She shagged him a few years back and if that didn't get him out of her system then doing it again won't work. I've advised her many times to end her relationship because it's shit but I think she's scared to be on her own and of what that will be like for the kids. I get that, but it's no excuse for an affair.