advise please

Kim
So I live with my so and I have two kids from a previous relationship. My so is sometimes so so strict with my kids it upsets me I talk to him about it and we just end up arguing. Of course my kids have rules but he goes over board he has two kids of his own he isn't allowed to see and I feel he's trying to take over mine. I love him to pieces and I respect the fact he has took on my kids and would do anything for them but I'm at my wits end. What would people suggest? Please no horrible comments