Boyfriend is always complaining after work

My boyfriend works at an oil change place, and complains about it after work every day. I know everyone complains sometimes and I get it - working long hours on your feet in the heat/cold covered in oil sucks. I definitely couldn’t do his work.

But every time I see him after work he’s pissed off. He’s not happy to see me, more angry about work. Me on the other hand, I’m a caregiver, and I deal with some gross stuff but I just want to enjoy his company and not stress about work.

I also find it hard to bring the subject up, because he said his ex-wife never wanted to listen to what he had to say, and she didn’t support him. So I’m trying to show I support him by listening, but at this point I’ve started to zone out.

He’s mentioned getting a new job countless times, but to no avail. Something happens where he can’t or won’t get the job. How can I bring it up without hurting his feelings?