He sounds very manipulative to me. Everything that happened on your valentines day sounds pre-planned down to suggesting you split for awhile. It is a common ploy (not just with A's) to address difficult conversations in public arenas - no matter that you stayed in the car the intent was to have dinner, and he just started talking a little too early.
I mean really, who plans a romantic date then 15 minutes in brings up a discussion of the current state of affairs? I'll tell you who one of two - someone with an agenda or an idiot.
This combined with the recent money issues with him wouldn't set well with me AT ALL. I don't believe he is spending 2k a month on your children unless he does the grocery shopping. I have to refer back also to what another poster said - who carries that much money around? Everyone takes credit cards even Mcdonalds and toll booths. What are all these receipts for the kids? So he is giving them money and telling them to bring home a receipt? Bah! Tell you what why doesn't the new Sheriff tell husband that YOU will now take over giving the kids money when they need it?
Don't buy the sullen sulky behavior either. Keep your antennae up more will be revealed.