I broke up with my ex 3.5 years ago and started dating someone 2 years ago. My ex and I have no formal arrangement but have a 50/50 setup in theory. In practice the younger child (8) stays with his me 1 night out of 14 ( because he wants a break from his older brother) and the older (12) one stays with me 6 nights in 14. My girlfriend is happy with me seeing the kids 50% of the time, though as you can see although I see at least one of them 3 nights in 7, it's not both of them so is not 50% - more like 25%. I want to see them more than the current 25% of the time and my ex is happy for me to do this but my new girlfriend does not want to "give up" part of her Sundays for me to see them for a couple of hours each Sunday. Is this fair?