I took my two (13 and 10 at the time) on what should have been our family of four's holiday (already booked) two years ago, two months after my STBXH left.
There were surprising highs and lows, things I hadn't anticipated such as us all crying as we sat down to our first meal out, caught out by how normal yet different it was. But we did things spontaneously that we wouldn't have done as a four, random bus trips up the coast, fantastic fish restaurants (he hates fish), foam parties on the beach!, black hole rides at the water park etc, memories I will treasure forever.
My DC made friends which left me time to read more than I have in years but I found that few adults spoke to me other than grandparents, I found that hard - why parents (couples) in family groups couldn't/wouldn't talk to me I don't know. There weren't any other lone parents where we stayed.
Anyway, my DC still talk about that holiday and want to go back to the same place. We've been away as a three several times since and had some brilliant times. I won't pretend it hasn't been hard sometimes being the only adult but as mine are a bit older and enjoy travelling it gets more and more enjoyable for us all.
That first time I really thought I couldn't do it, but I did and we had a great holiday.
I hope you try it OP. Other posters have given great practical advice re surviving the actual travelling.