What's the best way to tell my husband he needs to wear deodorant?

My husband was raised by a single mom who I gather didn't give him 'the talk' about how post-pubescent underarms are stinky toxic pits of death and misery and all things sacred. To be clear, this guy only wears deodorant/antiperspirant maaaaaybe once every 2 months. He'll wear it if he's dressing up to go somewhere nice, which we mostly never do. So yeah, we're talking 6 times per year here. One stick could last him a decade. Recently, we renovated our bathroom and I packed our counter things into a box, choosing to just move stuff back in as we needed them. His deodorant was the last thing in the box. Aside from this, he actually has really good hygiene. You just wouldn't know it.

We've always lived in fairly close quarters and both work from home, so over our 16 years together, I've formed and discarded strategies to get him to wear deodorant/antiperspirant. They are as follows:

1. Tell him he fucking stinks and to do something about it. This upsets him. He thinks it's rude/mean.
2. Politely inform him that some deodorant might not go amiss. Still seen as rude/mean.
3. Slyly push the deodorant into his field of view. This is passive aggressive, apparently.
4. Spray some air freshener and inform him that he's stinking up the room. He firmly believes it's his sweaty feet stinking up the room, despite it clearly being armpit odor.

It's like he's in some weird denial about his armpits. He claims he can't smell anything, so I assume he's noseblind to it. Despite that, it's also something he's clearly insecure about, as it's become a sore subject between us. He'll take a shower and then get furious when I say he needs some deodorant. "I just washed myself!" Yes, in a hot shower, and when you get out, you sweat! He can't seem to comprehend this. In his mind, 'shower' = 'smell nice all day'. But I can assure you, this is not the case. He's a pretty sweaty guy, and the stench coming from his armpits is downright vile. When you walk into a room, it straight up punches you in the fucking face.

I try taking him shopping and offer to buy as many kinds he needs to find one that he feels comfortable with, as he at one point confessed that wearing it sometimes made his mouth adopt a weird metallic taste. But he mostly just seems uninterested and annoyed at me for bringing it up.

I'm fucking dying over here. I love this dude. I want to be able to hug him without internally cringing away at the smell. It's getting ridiculous. I feel like I can't be straight up with him about it, because he's insecure and it makes him feel bad. And I feel like I can't be subtle about it, because it's passive aggressive. He's left me no diplomatic avenue for honesty.

So any guys out there ever been in this position? How can I get through to him? He's 42 now, so I half feel like it's too late and he's just never going to form a good habit about it. But that's probably not fair.