Any suggestions on how to handle this husband/sibling spat?

Suggest seeing your family without him. Don't go often. If they can't treat him with respect, then your place is with your hubby. Support him and ask him to support you by being more tolerant. YOU should be the one to "slap down" your siblings when they are disrespecting him. If he felt sure of your loyalty above your siblings (which is where it belongs) then maybe he will try to not agitate things by provoking fights. Ask him to help de-stress the situation. If he loves you he will want you to be happy. If you love him, you will want him to be happy. Work on it:)Good luck