You can’t forgive them, can’t forget, what can you do? You don’t like them either.
but they are your husbands family.
and it might affect your relationship with him.
you can’t expect to become a ghost in the family (him alone at all events and gatherings) and your relationship not breaking apart eventually
so here you are
you know very well you don’t want to see them but, but…
you have to go now and then. Not to all gatherings. But stuff like weddings, a birthday dinner or religious holidays. Big things like that.
dont go there thinking you have to like them or build a relationship, you are showing up purely for your own self interest, to keep your relationship.
have an array of neutral things you can discuss. the British love talking about weather, so that’s an hour gone (joking). Take the lead of your husband, let him talk to his relatives and you contribute something now and then, preferably nothing that invites a follow up.
dont talk politics or religion unless you have the same
if you are at a wedding, enjoy the food, talk to strangers as well, take a walk a month the flowers, you get it, keep yourself busy.
it’s normal to ask about the sons or daughter in law”s family, but it might not be for you. You don’t have to explain anything about your family either. It’s good they've backed down, it means you can show up and your wishes respected.
people here in this forum will keep telling you to forgive, build a relationship with your in-laws, but if you don’t even like them, how would you? Forget having a relationship, just be acquainted and show up now and then. For you and him, not them.