O yes, that problem can occur in every time, place and group. Jealousy is a form of insecurity and a lower charka reaction. I myself am still friends with all of my exes and it would sadden me greatly if I were not. Many women develop an authentic connection that lives far beyond the life of the love affair.
As for the less than flattering comments, I wonder if you are guilty of the same and if it is merely being reciprocated. If so - be nicer. What we give out does come back to back to us. We are denied what we deny others. Its the boomerang law of the universe. That being said there really are some mean people out there, if that is the case - avoid them whenever possible. I suggest you take the high road and try to see their higher selves. It may not may them like you more but I’m sure your lover will admire your effort and your emotional self-control.
Remember, she is with you and not them.