Yep - I'd be disgusted too. It's not just the literal unpleasantness and gag factor of horrid smells, IMO, it's also about showing respect for your partner. Like, they don't think you're worth a "bit of effort" and, in fact, actually seem to think you're only worth no effort at all.
The only excuse for this would be depression - or a physical ailment which left them so weak as to be able to take care of themselves, which, I take it, doesn't apply in your case.
How is this going to affect his new teaching job ? Believe me, all kids are adept at picking up any weakness and you can bet they will pick up on this. The grosser the better. How will he like being called "stinky" or worse ? Something like this where the kids snigger, recoil and gossip about him could actually affect the level of discipline he's able to maintain with them.
Back to you - why should this be "nagging" ? Adequate personal hygiene is such a basic lifeskill - and if you share your living or working space with anyone else, it also becomes a matter of consideration for them as well.
No way would I want to be in any way intimate with someone like that. I deserve a bit more respect .... in fact, on the very rare occasions when I've maybe forgotten to brush my teeth or have just eaten something strong tasting, I always tell DP if he tries to kiss me. If he then says he doesn't mind, that's different, but I do not assume it will be ok ..... & that's basic courtesy IMO.
Yuk, yuk, yuk ...... I can only echo what Essbee has said and try to persuade him that counselling may be a good idea, and this topic could then be brought up there. Sharing showers or baths isn't practical long term and doesn't get his teeth brushed either ! I'd feel if I got into that routine I'd be like his bloody mother checking to see if he'd washed everywhere.
WHY would anyone want to smell ?