I thought what's mine is ours!

Every time me and my SO and I argue he claims everything that's his. "Get out my car, my money and etc." I thought when your married and it's no longer I? He recently lost his job and I am joining the military as soon as I give birth for stability for us an our new baby. Even though he won't have a job I won't tell him don't use my stuff because he didn't buy it ?? Because we are married !! I won't punish and take away stuff and say that it's mine when we're not on good terms. Am I overreacting ? What should I do?