Isn't a honeymoon meant to be without the kids? Actually, also without the wifes ex? Maybe send the kids home with the ex and enjoy your honeymoon?

If the ex-husband has agreed to watch the kids while their mother is on her honeymoon, unless there's something else we're not being told, that means: 1) You and your wife won't have to spend your honeymoon looking after them. 2) Your wife and her ex-husband seemingly have an amicable relationship, and he's cool with her marrying someone else. 3) The childrens' biological father is still involved in his childrens' lives, which is great, and also means OP and him would inevitably meet. So honestly, that all sounds good. The only issue here, is that OP and his wife clearly didn't discuss childcare arrangements beforehand. Like maybe dropping them off at her ex-husband's before going on the honeymoon? Hopefully he's not there to be a third wheel - but a childminder, so your new step-kids don't end up being third wheels themselves.