First question: is Yeti fixed? It sounds like he is spraying, which is normally associated with hormones and the need to mark their territory. If he doesn’t know your husband as well as he does you, he could be a little possessive over you and not understand why there is another person trying to occupy your time. I suggest 1) fixing if Yeti is not neutered yet and 2) your husband spending some more time with Yeti, if he can.

I think your husband spending time with him is a good idea, also it can take awhile for all the hormones to balance out after being fixed. I read that it can take upwards of two months, so this could be some left over hormones. If he continues to pee outside the litter box, it could be something like the litter you use, the smell of the box (perhaps clean it?) or something else. I’d monitor him and maybe give him a treat when he goes pee in the litter box to reinforce that he must go there and not wherever he pleases.

I agree 100% with CinnabunMom. Lola used to pee on my boyfriend all.the.time. Like, he’d change clothes multiple times a night. Maybe distancing yourself slightly from him and letting your husband bond a little. It really sounds like he is just “staking his territory”. I’d try not to leave things lying around that might have your smell – like dirty laundry or blankets – and then go from there. I also have mixed up a white vinegar and water mixture (really no science behind it…I just dilute it a little and it hasn’t stained any of my stuff) and spray it on things (/everything in the living room) if she is getting over territorial and it seems to work and remind her that her cage is her home and everywhere else is a place she has to share with her humans.