Please do not assume this is not sleep apnea based just on how you think his snoring sounds. Unless you're a doctor or nurse with experience with sleep apnea -- get him checked out professionally rather than going by what you hear. You do sleep at some point and may be missing the sounds you think are signs of apnea. It's worth ruling it out professionally. If you are right, that's great, but don't take it on yourself to diagnose him.
This could be down to a lot of things and he really needs to investigate possible medical causes or changes that are affecting him. Rule out the stuff that could be medical before turning to managing this as part of your relationship.
Once he's been checked out thoroughly (which probably will involve a sleep study as someone else mentioned below), if there is nothing medical going on: Does he sleep on his back, his side, his stomach? It could be that his sleeping position and the position of his head on the pillow are affecting him. My husband only snores if he rolls onto his back and stays there for a long time. If I nudge him, he rolls onto his side and does not snore at all. (Like your husband, he did not snore when we were younger and I suspect that some of this has to do with changes as he ages. We got him checked and he does have some allergies too and that affects him.)
I also know of friends who say their husbands snore if they are lying too flat, with their heads in line with their bodies, but stop snoring as soon as their heads and shoulders are elevated.
Your husband's fast asleep while snoring, of course, so has no idea what sleeping positions bring on the snoring, so you can help by figuring out if he only snores in a certain position.
But meanwhile, since its sounds like it's loud and frequent enough to affect your own sleep, get him to a doctor as well as assessing his sleep positions.