Why don't you date while you have couples councelling sessions so that you can get all this lack of passion talk out of the way with someone who can help you to get back on track. At least then you'll know you're both making a concerted effort to reconcile and rekindle the lust.
I suggest you stop taking the children when you go on a holiday to try and re-connect with one another. How can you concentrate on one another when you have to toddlers to worry about? This should be about you and her right now... not you, her and your children. Take her away for a mini-holiday just the two of you, make it romantic and sexy where she doesn't have to change diapers or make sure her kids are'nt drowning.
Good luck, I hope it works out for all of you.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion