Nugget, you and I don't really know each other, but it seems to me that your W and you have a thing going on already? you are telling her she is beautiful and calling her nicknames? you are already flirting with her.
There are a couple things you could do. if she is really comfortable, then you could just directly ask her out. Here's a scenario: a fundraiser. maybe someone at work is a volunteer for a local school. Maybe there is an art auction to benefit a boys-and-girls club. The museums have fundraisers, too. Etc etc. Preferably an evening event, where you have 2 tickets. Preferably someplace where you can sort of be anonymous; like it's not gonna be an awkward situation where you are introducing her as your ex-wife. And you say to her, I have these two tickets, I need someone to go, I was thinking of asking....
Two ways to go here- you could just ask her directly. or, you could take a longer term view and say "I was thinking of asking <someone else>; and I'm a little thoughtful about what our son will think." Something like that. You'd have to be prepared for her response. If she says "oh, he'd worry." then you have an opening to ask her. If she honestly doesn't care, then you would have to be prepared to ask someone else.
This is a "date" sort of, but not really.
Another thought - find new stuff to discover, and find ways to include her. This brings back the newness. New restaurants. New places to visit. Start playing the guitar. Whatever. Newness is the thing. Discovering new stuff with someone is one thing that builds attraction.
just a couple ideas. good luck to you.
M 43 S14 S13 D11 D7 Divorce final: Jan 2009 Making it up as I go....