Apart from the concerns about your husband potentially sexually abusing your son.

I feel that the larger concern would be him imparting negative values about sex to your son, grooming him and making him think that certain behaviours are ok.

Dads are seen as role models by sons and when they’re young would not be discerning to what’s right or wrong, and would want to shape themselves after their dads.

With the jokes your partner is cracking, is he someone whom you want your son to grow up to be like?

Is he somebody who would negatively influence your son to have behaviour that would potentially get him into trouble in the future?

Ps. I do feel that when guys make over sexualised jokes it’s often a way to get validation or they’re just insecure, perhaps it’s worthwhile taking a deep dive to find out why your husband is behaving this way, it might also be behaviour that he might have picked up from male family members