I have seen few people of the same kind who dont care abouth homo people or oppose the lgbt community openly but get insanely pissed of if someone close to them is a lgbt . This case here is a bit different and i probably appreciate op for being with her son as unlike many other teen coming out at homo he atleast has the support of a single parent and a few member of his family ( well i guess op's other children support it or do they know about it ??). Also op's son can not deny his own identity just because his father does not accept him and op getting angry on her husband for hitting her son is completely undeniable insyinct of every mother its not wrong .

But op's husband asking for a divorce just because op supports her son is like stupid. He maybe homophobic so he can kick his son out but pushing his wife out shows that his ego or stubborness is taking over him and that seems more important to him more than his family.

So here is my opinion ( totaly what i think like sorry if it offends you ) Op loves her husband but her instinct for her son takes her over and her husband is too stubborn . Well i guess its now just a one sided realtion as his anger towards you might increased inside him so most probably there are least chances that he will cancel the divorce if you still support your son ( which will be the case i guess ) and hence there will be mutual love and respect no longer. So you can speak to one last to see if he can accept to any terms like YOUR SON GROWING IN YOUR MOM'S HOUSE so in that way you can syill support him ( again here i guess your mom also supports your son being gay) But if it doesnt work all i can think of is divorce ( pls comment if there are any other option you can think of ) Also take custody of your other children ( u cant let a stubborn dad take care of them ) moreover they are less than 16 as this is your eldest son .