parenting differences

my boyfriend an I have a daughter on the way but i also have a son but his bio father is not around my boyfriend was nice enough to step up to the plate an help me raise him. we havr some parenting differences. he more strict on me he is Portuguese an there culture is stricted. but im worried because of our differnece we going to have time also raising our daughter. i do always put ky 2 sense in when it comes to hik parenting. an he doesnt with me. i dont do that well that your kid not his that not right in my eyes. that certain things be okay with my son an more with his daughter cuz there blood. that his kid as much as mine an that how i feel anyways, how can we co parent better. me an him both also have a problem yelling when we upset weather at each other or our child. i would like to work on it just not sure how to. either. cuz iour dont want newborn daughter around yelling. any advice.