Why does my husband say things he doesn't mean?

Newlywed and trying to understand. My husband tells me very harsh things when we are disagreeing (I am very calm and emotionally contained when we disagree but he is not, very high anxiety person) and then recants his statements shortly after. So far he has insulted my parenting, my job cleaning the house, and said he will not stop using pot even though he knows there is a bad history of genetic addiction among the males in my family and it's my greatest fear for my son and I don't want it around him. He apologizes later. But I feel like I can't get a straight answer from him and I don't understand. I just want to relate to why somebody might say something they don't mean because I really don't do that (really!).