Opinions needed

My fiancé and I have been together for a year and a half. Our homes are about an hour apart and we split our time between the two homes. We both have two children, mine are 19 and 17, his are 14 and 13. We have the children on opposite weeks, allowing our arrangement to work. His children are very dependent and needy, and he is afraid to parent them for fear they’ll say they want to go live with their mother full time. Our relationship is great aside from his children. He sees the error of his ways, but is afraid to make the change. I get very upset and can’t see past my anger and hurt feelings when something goes wrong, such as him not communicating or making a decision without me. I feel like I’m just along for the ride many times. This morning we got into an argument on the phone, something silly to him and important to me and something that we had fought about previously, his son heard me and texted his dad to see if he was okay. This angered my fiancé and although we “made up” things are still tense. How do I stop being angry and hurt and just let things go? I know he loves me and isn’t doing things on purpose.