Jayne only hugs Simon on the bad days.
Most days he can deal with it on his own, maybe with just a few tears shed while by himself in his bunk where no one can see but him.
But some days, like when he sees a dress that would be exactly the sort of thing she would wear, or on the anniversary, he can't help but reach out to the one man who can understand just as he can how much it hurts.
It's only been slightly over a year and yet he knows the hole won't ever go away. He knows that if he didn't have to protect the rest of the family that he would join her, but she would have wanted him to make sure they were all safe and so he stays.
Jayne only hugs Simon on the bad days.