I have name changed for this because I am paranoid that one of the people in question will recognise the situation then go back and see all of my posts!
DP has a female friend who he has known for about 15 years and who I get on very well with. I have a friend who I have been close to for around 5 years.
Around 6 months ago DP had a birthday party which both these women attended. They had met a few times before but only at big events like this so they are not friends. My friend's (now-ex) DP of 6 years wasn't there and she was talking about how they had been fighting and it wasn't working. DP's friend was joining in and quite strongly saying that she deserves better and that she shouldn't be afraid to end it. My friend and her DP split a few weeks later (not married, no DCs).
About 3 weeks ago I saw on facebook that DP's friend and my friend's ex are "in a relationship". My friend also saw this and is understandably upset.
My friend has also told me that I should cut DP's friend out as she is "a snake" and is probably "after my DP".
I am struggling with how to handle this. DP's friend has been a great friend to DP over the years and is now one to me too and has not done anything wrong - there is no evidence to suggest that there was any cheating involved and she is not friends with my friend. On the other hand, my friend is uncomfortable with us socializing with DP's friend and her ex as a couple which I understand.
How would you handle this?