Marriage problems, desperate for help?

[Ilovemymarine]

I am going to sum this up as short as possible. My marriage is failing. And the main reason is because my husband has a daughter from a previous marriage, which I adopted. I met my husband when I was barley 18, he was almost 25 and his daughter was 2. Anyways, we got married, which we should have dated longer. I basically became her mom right away. We have a two year old together and the last one on the way. But I am so miserable. And this is why. I cannot discipline, tell, say anything to his daughter without him turning it into a fight. I am mean, this and that, when I am really not. But when it comes to my 2 year old, it is a different story. Today, he ticked me off so bad I wanted to scream. She got home from school, and I told her to get started on hw. She wanted a banana, I gave her one, she wanted more, I told her to wait for dinner. Husband flipped out. It is like this all the time. I can't tell her anything because he flips out on me. But I tell MY 2 year old no, that is fine
It is like this everyday, so as you can imagine it bottles up inside. To be expected to be someones mom but everything you do is scrutinized. I would have left if it weren't for the kids, but I just can't now. I am so fed up. This is causing me anxiety and stress. And no man is worth this. I am 22 years old and have devoted my whole life to him. He is military so I go where he goes like a lost puppy. I need advice, and soon. This is tearing me up inside. And it effects the kids as well. Please any advice I will take with respect.