I am not sure what it is but my W now says I am the fun dad and I only buy my children's love. I think she has some serious mental alienation because I never ever had to buy their love and she is making me feel even worst than during our domestic separation.
I remember how hard it was when my kids were little. It seemed that all I ever did was wash, cook, clean and then start again. All this whilst two children were constantly wanting my attention. I couldn't even go to the toilet on my own as they didn't like me being in a different room. I use to wait until they'd gone to bed, pour myself a glass of wine and not finish it because I was too tired and all I really wanted to do was sleep. I can only imagine how much worse that would have felt if I was on my own and my H came every two weeks, took them out for ice-cream and walks in the park or to the zoo or whatever. It would [censored].
So, understand your W does not have some serious 'mental alienation'. She is tired and frustrated and sees you and the children having a good time. But, having said that, her frustrations are her problem. Her tiredness are her problems. They have nothing to do with you and you have done nothing wrong.
Carry on as you have been. Giving your children love and affection is never wrong.
Maybe validate a little.
"W, I understand why you may think but I only see the children every two weeks and the time is precious to me. I want to make them count. I am not buying their love. I am showing them that they are loved."