If divorced people don’t want or aren’t prepared to invest time in a relationship then they shouldn’t try and pursue them because I’ve done nothing wrong, he’s making me feel like shit - not the other way around.
He should be with a person who is in the same situation or would be happy with a day here and there.
You've not done anything wrong but nor has he.
Just because he has kids doesn’t make him holier than thou or mean that he shouldn’t also make sacrifices to make things work.
He probably thinks that not seeing his kids 50% of the time is a sacrifice.
I know you've not asked him to see the kids less but changing contact routine affects his kids and ex as well as him. There may be a financial cost that both parents bear if contact is changed. You're not unreasonable to want quality time but it sounds like he thinks that quality time can be achieved in the 3.5 days that he doesn't have the kids.
With a man who has 50/50, I think you can't end up being the "good friend " to the kids. You'll end up at least doing the mental load of a parent like thinking of a dinner that suits the kids likes and dislikes and popping their laundry in the washing machine to save your partner time.
I bring up this point because my ex has a long-term gf who doesn't want to be stepmother to our kids. The kids used to find it very awkward that she was under the same roof but not cooking, cleaning etc when they were brought up with such stuff being collaborative- everyone scrapes and loads dishwasher and so on. It got to a point where she goes to see her elderly parents every time they visit. (The kids heard them argue about this ) They will never be a blended family but as the kids are now teens and she has no desire to go to weddings, graduations etc we plan to continue this dysfunction as if nothing's wrong. It's been 5 years since the kids have seen her.