Posting here as I’m not a lone parent (remarried).
Last year we swapped Mother’s Day and Father’s Day but mother’s day fell on my weekend anyway this year. Father’s Day also falls on DS (10) weekend with me. Ex hasn’t asked for time with DS on Father’s Day, but equally I haven’t offered. DS asked me if he was going to see his dad on Father’s Day, I had a nice day planned for me DS and his stepfather (my DH). Am I being U not offering it to the ex?