What to do about son's ex?

[CM97]

Son and his gf recently split after 6 years, (no kids, weren't living together but planned to move in together over the summer) and she's been part of the family for the last 5 years and we are fairly close. My feeling is that she's made her decision to leave him and that decision means she can no longer be part of the family. Am I being too harsh? I don't see how we can carry on with the same relationship that we had previously.

Well you’ve changed your story. Either way I don’t think there’s any confusion here - she’s finished with your son and not responding. She’s just not that into you

I've messaged her a couple of times asking how she is, and asking if she wants to talk and I've not had a reply.

This is quite a peculiar thread.

OP you say she can't have it both ways and that your loyalties lie with your ds.
She doesn't appear to want to maintain a relationship with you so I don't know why you are saying this. It makes little sense. She doesn't appear to be demanding or requesting anything. The only people who seem to want to maintain a relationship are your other dc.

You've also said

I've messaged her a couple of times asking how she is, and asking if she wants to talk and I've not had a reply.

And then

I've messaged her twice. The first time to say I was sorry that they had split and take care. She responded and asked if I wanted to chat

These contradict each other. Either YOU asked if she wanted to talk and she didn't reply or she asked if you wanted to chat. Why are you saying two totally different things?

Just leave her alone. She has broken off with your ds. She hasn't responded to you.

You’ve done all you can then, more would be intrusive. The siblings can keep in touch if they want to.

It's fairly normal if your child breaks up with someone to not see them again or be friends. I'm sure she knows she's not one of the family.

MIL DH and I did actually stay friends with one of BIL's gfs who'd been a childhood friend of DH and BIL and she's recently become one of the family again about 20 years after her and BIL broke up, (following her recent divorce from someone else). BIL is also friends with her now.