I agree that something doesn't quite add up with your numbers as is, but to provide a guesstimate:
If we take your listed expenses and back out the day care ($2400) since you say that will go away that leaves you with $7,100 a month or $85,200 a year annual expenses.
Assuming the standard 4% withdrawal rate (recommended by MMM) or using alternate percentages (lower being more conservative and higher being more risky):
3%= $85,200 /.03 or $2,840,000
3.5%= $85,200/.035 or $2,428,575
4%= $85,200/.04 or $2,130,000
5%= $85,200/.04 or $1,704,000
Aiming for retirement at 50 I would normally recommend looking at a 3.5% withdrawal rate however your NW is almost at that target so you are very much on track and basically could FIRE any time now.
I would recommend as ysette said really focusing in on what a true yearly budget looks like for you and DW and then see if there are things you could really cut still. Also just planning out what you will actually want to do/spend money on in retirement.
My one question too would be why such a small amount in your 401k's? They would have to be truly awful to not max those out, maybe they are just new to you because you switched jobs or something like that but I would strongly recommend maxing them out for the next 15 years. Assuming you hold to that goal because depending on how much you and DW like working there really doesn't seem to be any financial necessity to work that long. Just some financial organization that needs to take place before then.
Keep up the good work