Sorry my mumsnet is jumpy today. Long story short. Split with ex when ds was 1. Contact was sporadic due to exes job. At 3 I had enough and hv involved. We agreed for him to do more. Fast forward a year and he's met someone so started doing more. We agreed 2 nights a week and one weekend a month. His weekend is Saturday morning to Sunday night. However I'm not getting a weekend next month as he has 3 weekends of nights and a wedding. Aibu to think this isn't my issue? I've contacted a mediator as he says he won't change it. He has history for this and needed mediation over a house with anther ex.