I appreciate very much that you don't blame or stigmatize him but rather see him as doing typical 13-year-old stuff.

Two things occur to me:

If you think you have overreacted and/or have been hurtful, have you given him genuine apologies? If not, I suggest that you always make it a point to apologize to him, when people are calm.

If you apologize, don't try to explain or in any way try to justify why you said what you said--just apologize for saying it. I think kids learn to respect adults who give genuine apologies.

Have you been able to discuss with your husband that he always takes the boy's side? I agree that one wants there to be just one team. If the two of you cannot come to a mutually trustful understanding, what would you think of couples counseling to help reach one?