Hugs OP, you know your husband best and how he'll react. Do you think he would be able to eventually get over it, or do you think he would damage their relationship with him? If it's not worth the drama, I'd just let your kids come out if/when they want to on their own terms/timeline. Or if you think he could learn to accept them anyway, maybe you could you could encourage your kids on being more open with him.
Both my children are gay. Well, DS20 is gay, DD17 is a trans man, so I guess I should say DS17. DH and I are politically opposite and it's been a very challenging half decade since the first one came out (on his own in a letter to us). The second time, it was actually the school that outed him, in the most uncaring awkward way, catching us by surprise. We all knew DH wouldn't receive the news well, so I made sure both my children knew I would love and support them no matter what.
DH is convinced its the liberal agenda to push gender confusion to youth to depopulate (yes I know

). I argue I have gay uncles, a trans aunt/uncle and two gay cousins older than me, and older than my parents for a few of them, in various parts of the world, including conservative Christian countries, so maybe it's genetic... and maybe the liberal agenda is to make everyone in the LGBT+ population feel included in society and he's just twisting it into a conspiracy. It has been exhausting, I won't lie.
But, somehow, after years of heating up and cooling off about the subject, he seems to have reached a point of acceptance, or realization that he can't control anything about their gender status. I've encouraged him just to be kind and focus on what bonds they do have, or risk severing his relationships with them. I hoped he would come around, and he seems to be.