I usually don't judge others with what I hear, but with what I think and feel after meeting up with them. I'd usually give others the benefit of the doubt. I don't feel comfortable with all of hubby's friends, but I have to be nice to them. Some even came way before hubby and I met. Some we're even friends of his exes.
When it's meeting up time, I see to it that I don't get derogated or slighted even if they are all older than me, or even if they are much more accomplished than me. (hubby's older than be my almost 5 years and a practicing lawyer). I believe in my own capabilities and that I was never insecure of who and what I am. So far, nakukuha pa naman sila sa taas nang kilay ko. Nice ako, pero super frank. If I don't like it, I'd say it, even if it's against the opinion of the majority. That's how his friends know me, so they're extra careful. I believe it's best na sumama ka if hubby wants you to. Give both yourself and them a chance to really know each other. Find out why things didn't work out between them and their partners.
If you don't feel like joining them, then don't force yourself to do so, rather than ruining your night.