Isn't this backwards???

So my partner & I just started struggling financially and I got a job last week that I really enjoy. We moved to a new town recently & have both been trying hard to find work. He only has manager/retail experience, whereas I have medical certifications & background so it's a lot easier for me to find work where we live & we both decided I'd work & he would watch my son while I'm working (I only work 3 days week).

Anyway, whenever we're together all day, he acts like he can't get enough of me & is loving and touchy feely, etc. When I get home from work, or even running errands for a few hours, he acts spiteful in a way I guess? I'll come home & he just says hi and gives me a kiss and that's all the attention I'll get the rest of the night. I guess I just don't understand why he acts backwards. If I'm home with him all day, he's all over me. If I'm gone all or half the day, he acts like I've been home all day and he's tired of me. Is this some kind of weird separation issue??

Idk what to do cuz when I get home I genuinely missed him so I want his attention & to give him my attention. This keeps happening & when I talk to him about it he just says sorry, you don't deserve that, idk why I'm doing this, blah blah. That doesn't explain his behavior so it doesn't really get resolved... Help?!