Sure some things are unavoidable, you just have to do your best. You will have vacation days, personal days, maybe comp time, and even trade shifts with your fellow Officers.
I was very active with my kids. Being involved in my kids activities was very important to me. I sometimes would trade a shift or take a day off. It also helped me that I had supervisors that had the same belief that family was very important. You just have to make it work.