my friends HATE my ex

my friends hate my ex and me and him broke up on amicable terms and I don’t hate him. but they all hate him. which I understand because they saw how I hurt after the breakup and they saw that he didn’t treat me the way I deserved, but idk. it’s his birthday this weekend and I asked my friend if I should tell him happy bday and she said “ew gross no, he doesn’t deserve that from you”. sometimes I just wanna talk about him and our relationship without them dogging on him because I did really love him and I will always care about him. I understand they are just watching out for me but I feel like I have no room to vent. and i’m still hurting a little from the breakup so I just don’t like hearing people talk bad about him cause they don’t know him the way I did. what should I do?