I have a 50/50 arrangement with ex.
For myself, I do often wish that ex would just disappear or only do EOW. In some ways I do think that would be better for the DC because I get the impression that things aren't great at his, but not bad enough for them to complain about and they're good kids and loyal to both of us so don't want to say anything negative about him to me.
I hate interacting with ex and would gladly never see him again ever (if it were only about me).
For the DC, I recognise that although ex is pretty crap (in my opinion), it's probably still better on the whole that they spend equal time with both parents. They can tell themselves that he wants to be with them, even though he's currently planning a relatively extravagant holiday with his new partner (just the two of them) that means he probably won't be able to take the DC away on a holiday too (due to cost). DC1's face when he told me about this plan also told me that DC1 is getting the message that dad's partner is more important than the DC and I can tell that hurts. But DC won't say a bad word about dad.
I certainly didn't sign up for part-time parenting when I had them. I hate that I don't see them every day, although I am past crying about it every week. I absolutely believe that that's something other people experience and express.
At the same time, I recognise that I get a break, get time to myself and have been able to establish a new relationship with a lovely man. It is possible for me to be grateful for that and simultaneously sad that I only see my DC half the week. Two apparently contradictory things can be true at the same time.
It's much harder doing all the parenting alone full-time or close to full-time. I know that. But it's also shit when you hear your DC telling someone else "of course not, he never goes to anything" when they ask if DC's dad was also at some school event.
I think when people make those comments, it's because they have moments where they do wish the ex would go away. And maybe also because they think you might feel better if you know that just because the other parent does see their child, it doesn't mean that it's all sunshine and roses. It's a different kind of hard.