I didn’t ask their dad, but it would have worked ok because we were still friendly and can both put the kids first. We reconciled after a couple of years apart though, having really worked on the issues that split us up.
I did take the kids abroad on my own while separated and while I was nervous about it (two kids with complex needs), it actually worked really well. I used special assistance at the airport on both sides, which got us through security, passport control and to the gate really quickly. On resort we just set expectations really low - we looked for activities to do but if the kids needed a day in the room that was fine too, were really flexible about food (and ate in our room when needed).
I didn’t feel lonely because I had the kids, and chatted to other adults round the pool or the bar. Things that worked well was going to a small, self catering place with a restaurant on site so we could eat close to base, make easy meals in our room or go out for food depending on how we felt. Daily budget for drinks and snacks, and bought snacks for the room from the local supermarket.
What didn’t work at all was All Inclusive, it was too busy, the restaurants were too noisy and too much choice of food. My kids couldn’t choose something to eat because they were so over stimulated.
It’s scary to think about doing things on your own, but very liberating to manage it, even if everything doesn’t go like clockwork.