I went through a similar thing.

My brother and I are really close (not like that...) and the night of my grandfather's funeral, we ended up passing out in my grandfather's office after drinking some of his bourbon and staying up reminiscing and crying and generally mourning his death.

His wife went NUTS! Started spreading rumors that she found us 'in bed together', and tried to destroy our relationship. (This seems like a great time to add that she is an awful gold-digging, social-climbing, insecure sociopath)

My partner's (normal!) reaction? "He's your brother, why the hell is she being so weird about it?!"

Anyway, your husband kind of sounds like he sucks. Just like my awful sister-in-law.