blended family, troubled marriage..how do you leave without hurting everyone?

Well where to start..I have been married going on 2 years now at the end of this month and I should be super happy to celebrate another anniversary but I am sad and tired. We have 3 amazing kids but we can't seem to keep it together. My husband has a Daughter (7 yo,) I have a daughter from a previous relationship as well who is also 7 yo. We now have a son together who is a little under a year. We said we would never put our son through a divorce but its easier said than done. It seems that everything I do is wrong and I dont know if I should continue to jump through hoops. I went from being a busy body working woman to a stay at home mom who cant be a mom to both my children just his (our son) Everytime I even bring up my daughter it starts an argument. My husband controls when I see her and how many days she cqn spend the night a week (2.) He calls all the shots with his daughter and I dont say a thing bc I understand its his child as well. I am not allowed to take her to his family gatherings (even tho his family tells me to) because he says they are too niceto her and she Isnt even related to them. Why does his family realize her and I were a package deal before getting married but he doesn't? He is constantly telling me I am a piece of poop mother to her and I had no right having a child when I did so its my mistake. Many different versions of that. I would like to leave bc I feel like it is jeopardizing my relationship with my daughte r and none of the kids need to see us arguing. I feel guilty for the kids if I go. He is constantly telling me that this marriage is **** and he wants a divorce and that I am every word in the book. The next day comes amd he act like he never said a thing. After having my son he said I changed and I thought so too but just figured it was me maturing and becoming more of an adult. I forgot to mention I am only 25 and he is 32 with 1 divorce under his belt. Anyways I was feeling sad as timr progressed so I told him I wanted to see a dr about postpartum depression. There were so many changes with this pregnancy.his response was "I dont want to be married to a crazy person and its just in your head." The solution..I wasnt able to go to thr dr. and at least talk about it. I am afraid of leaving bc I gave up everything for this marriage (my job, my car, my studio room, my friends, my original body, my clothes and so much more) but at the same time my kids are everything and all that stuff is replaceable. I am scared of doing it on my own but I know I can do it. Well this is getting long and there is so much more to say but what do you think? Is this normal for a marriage still in bloom or am I just prolonging the inevitable? Thanks for reading

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