I’m confused with this marriage

Hi I need guidance!
Been married for almost a year, but I’ve been with him for 3 years and we’ve lived together for 2 years. He has a daughter who’s 8 and lives with us.
We both work full time, both in the army so we’re quite busy. My husband is currently gone for 2 weeks, and I’m the most relaxed and happy I’ve been in a while, even with his child being around. My house stays clean, I don’t have to pick up after anyone etc. We’ve gotten into multiple fights about this issue in the past. About the fact that he doesn’t help around, that I have to nag him like a mother for him to help around just a bit. Every-time we fight his answer is “ sorry I’m so shitty “ or “sorry I’m not good enough” which makes me feel utterly shitty which I shouldn’t.
For the last week I’ve been thinking about separation and such..
But I feel kinda trapped, like I don’t know where he and the 8 y/o would go or where I would go..
Help? Anyone has had this issue in the past, and has any guidance?