Coparenting - asking permission

This month, in the adjustment to co-parenting, I found it is a challenge for me to ask for permission.  I don't have to ask for permission for things in my life but if an activity involves the children, I do.  This week for example my brother and his family were going to the temple for the first time.  It was a super fun day! But I did not ask if I could take the younger kids with me.  I simply assumed it would be fine. However, I felt twinges of guilt for not asking him personally if I could have them for most of the day Saturday.  It was an important family event and they had every right to attend. He was kind and did not argue about it but Saturday was part of his week with the kids.  I am going to have to make a better effort at communicating my plans.  Co-parenting is tricky and has real challenges, but it is the best option for my kids.