upset with this situation

My fiancé makes me feel like his kids have to be my own they have a mother and their father... he cancels with their mom and has me do everything for them clothes shopping, school supplies etc! I run them to daycare every morning making myself late for work and getting in trouble. He doesn't care one bit instead rubs it in my face that he picks them up and is alone with them for an hour and a half while I work. I feel so stressed all the time so I tried to get him to enroll his two kids in the same daycare I work at so I'm not late and kids are where they need to be on time. He got all mad at me... I'm trying so hard we aren't married yet and he places all the responsibility on me because I want one more kid. I feel like I'm being punished constantly by him. I love helping but it all feels like he wants me to do all the work while he stays up all night drinking wakes up hung over and doesn't want to deal with them. This morning he got angry and knocked my coffee creamer out of the fridge and it spilled inside the fridge on the floor every where... one morning I asked him to take his kids to daycare so I didn't have to take my sick child whose running 102.9 temp. On that note yesterday he yelled at me for taking her and his daughter to the dr told me my daughter didn't need seen long behold she had 103.0 temp and his daughter was fine :(