Was my friend out of line?

Your friend is a horrible person. Her new boyfriend is a horrible person.

Ask yourself, are these really the type of people you want to associate with?

I was not a fan of your friend when you said married man... But wow she managed to get even worse!

No child who of that age, who’s father has shacked up with another whore, would ask her to go to their sports day.
rethink your friends, because this one, is vile,

Your friend is making a terrible fool of herself over this man. Two months in and she's providing a home and parenting duties for a cheat who probably only showed up on her doorstep because his wife kicked him out. If that's not enough self humiliation she's publicly trying to mark territory which will be highly transparent to everyone who's sees her.
If you care about this woman you should probably be concerned about what is wrong with her to bring herself so low.

I agree with your thoughts on this. Your friend seems selfish, immature and nasty. I wouldnt be holding back - but then me and my bestie call each other out on shite like that!

She'd be an ex-friend. She's awful.

Or the new girlfriend is so insecure she can't stand the thought of her 'boyfriend' being anywhere near his children's mother.

Honestly? I think it is up to the husband - he chose to have an affair and leave his wife.

BUT choosing to go to sports day to see children who aren’t yours is an extremely weird thing to do. I have a friend whose husband left her for a younger woman - and they make a point of both turning up to all his children’s events (this really upsets my friend). We (her friends) are quite bemused by this - I can’t imagine going to an 8 year old’s school play if they weren’t my child. Presumably they (the husband and his new girlfriend) think it makes them look like more of a couple.

If the OP's friend believed in the sisterhood she wouldn't have been shagging another woman's husband in the first place.

Your friend is a psychopath.

I wouldn' t want to be friends with someone so deviod of empathy and with no sense of what is appropriate behaviour. It must be a shock to see your friend in this new and unpleasant light.

Bitch, cow etc are standard detrimental nouns for deeply unpleasant women. Men have their equivalent.

This isn’t about the kids. It’s about her actions, behaviour and attitude to her partner’s ex. The mother of his children.

The married man is vile for doing this to his 'ex' wife and children. The friend is vile for bad mouthing the mum, meeting the children so early, and especially going to the sports day (clearly wanting to rub the wife's nose in it). Both sound horrendous and I definitely wouldn't want to be mates with that.

Your friend might find out that now she has moved up in the pecking order she has created a vacancy beneath her for a new girlfriend. Karma and all.

You should have said something OP.

This isn't someone you want in your life anyway.

😳😲 wowsers!
She's sounds like a nasty lady !
I would steer clear of someone like this !
She is deluded ! And deffo can't see what she has done is wrong and the husband !!
That poor woman !!
If it was me and ow turned up at my kids sports day I think I'd wud have lumped her one lol 🤣 🤣 🤣 🤣 !!!!

Bitch, cow etc, highly misogynistic language.

They aren’t HER children, the father should have stepped in.

Your friends a cunt and I don’t think I’d of had the self control to not tell her that.

I would not have her in my life anymore. She sounds vile.

The friendship would be over. I'd be telling her just how vile an individual I thought she was and wished her luck for when he inevitably replaces her as well.

I would not be giving my time to people's who do things I just can't accept

Add to that the OP appearing unbelievably morally clueless and they all sound like people you would want to avoid.

Sums it up
i’m not hardcore about punishing affairs forever, and accept nobody other than those directly involved know their specific situation

however there are casualties in all affairs, and anyone with an ounce of decency and dignity would not have attended.
school is their mum’s territory, to brazenly attend is incredibly cruel.
plus the children have been put in a position where they are being taught not to respect their mum, and could have been subjected to seeing their mum very distressed.

i could not be near your ‘friend’, she’s a wrongun

Shabby, very shabby.
You'd be well advised to cool your friendship (is it a friendship when your values don't align?) with her or you'll be expected to pick up the pieces when he does the same thing to her one day.

She’s clearly living in a bubble. Personally, I wouldn’t be there for her when it bursts.