Does anyone know why he would be doing this?

I go throw that sometime,but only when I am working a lot or long shifts. The same for her. So I don't think anythings wrong with it in less he's is getting from some where else.

He could be cheating, that is one of the signs. He feels guilty and doesn't want to disrespect you so makes up excuses, but there is a combination of things that guys do, like trying to be more private, hiding their phone, no more PDA or affection @ all, not wanting to hang out. But regardless, it shouldn't be an all-time thing if he really loves you, he should want to express his love.
Hope I helped
Luv kan