Hmm I have been thinking a lot about this recently for myself as I signed up to a dating site last night (just to browse/no picture). I am not writing this to criticise you Complex, just giving my thoughts.
I would not be dating at this point. Others may of course disagree. You live with your W. She will not see it as a casual hang out with someone should she find out, she will see it as you moving on. Maybe this will be a wake up call for her. Maybe it won't. Who knows? It may be the thing that tips her one way or the other. It is likely to inspire jealousy. I don't think getting your W back by her being jealous is a healthy thing, should she come back at all. I think ultimately jealousy would turn to anger and a more determined mind to follow through on things.
I think so long as you have a desire to sort out your marriage, testing the waters with someone else is not going to work in your favour. Sure, it may give you a confidence boost, and that's good in the short term for your self esteem, but I think that could also be gained by hanging out in a group, doing certain GAL activities, and plenty of other ways.
Having said all of that, ultimately it is your decision of course. I hope you have a good time and gain what you want from the experience
BD - 30TH JAN 2015 S - 30TH JAN 2015 PA CONFIRMED - 16TH FEB 2015 (SINCE AT LEAST OCT 2014) CONTINUAL TALK OF D ME: 31 W: 28 T: 10yrs M: 4.5yrs D:5, S:6