Serious need of advice. Long post

Im at the worst breaking point of ny life. I have been with my fiance for 13 years we have a 4 year old daughter and i am 5 months pregnant with our son. My fiance has a serious internal trauma that makes him a really miserable person and the only time he will snap out of it and fake being happy is when he feels that i am done. I dont doubt his.love for our daughter. He is very totalitarian in his.parenting. i am strict but i am also loving and gentle. Our 4 year old loves him to.pieces of.course but she gets sassy back to him because of the way he talks to her. So he loses his mind when she does and threatens to smack her and tells me im a " gentle parent". For about a year now ive tried to stick to the bible stating that a mans way of parenting is different than a womans and it should be that way. So ive let him being a little louder and little more strict. But its getting so bad. Verbal abuse bad in my.opinon. please give.me your opinion about it. He refusesto give our daughter " space" when she is angry. And when she lashes at him for getting in her space he gets even angrier and she.doesnt know what to.do. last night..was it. It was the last straw for me. Our daughter didnt sleep barely at all the nifht before and didnt nap at school so she was beyond exhausted and it was about 8 pm i was getting ready to put her to bed. And he asked her sometbing and he made a grunt sound at him which is the sound she makes when she wants to be left alone. He refused to leave her alone. So she got up started crying really hard and ran to the corner of room. And i said " stop argueing with her, shes 4 years old and exhausted " and he stands up and says " fuck both of you". My mouth hit the floor. And i took her up to bed. Went.downstairs and said decide tonight wether you want to maintain this house and I leave or vise versa. I.meant every word i said. Told him he better never talk to her like that again. Well i ignored all of today. And then tonight..she was again tired 8 pm. And we were coming down the stairs cause i was gonna let her play for a couple more minutes. And he had already got an attitude with her so she turned around and made a face at him. And he lost it again. And i told him " how.do expect her to talk to you, when you yell like a psychopath and give her no chnace to speak or anything, you are teaching her to disrespect you, by disrespecting her" And he came and yelled at us both in the toy room and told me i was a worthless gentle parent( which im not, i discipline her but i also treat her like a human being. Its okay to.be angry, its okay.to.need space, its okay to.feel this way) he disasgrees.with that way of.thinking completely. And my precious child under her breathe said " daddy doesnt like us any more" and my heart fell to.the floor. Cause despite his behavior. He is a really good father. He does alot with her. Teaches her alot. Im stuck so hard on whats best. Its just getting to the point where i cant wait for.him to be at work because i.know we will have a peaceful evening. Theres no one there to.yell, bitch or complain. Im dreading birthing this precious human and have contemplated to many time putting him up.for.adoption because i.know my SO will not.be able to handle it all.