what to do with a single girl if I'm married??

Confused here! Im married w/ kids, but I do have an open marrige. My wife knows everything about this. I met this girl a couple of months ago in a business environment that we meet once aweek n every once an while we can have individual meetings to talk about business n we have after hours events etc. I want to date this girl cuz I like her alot n if it goes into sex, well thats good too! If i wanted only sex, then I wouldnt be messing with this one, I would just pick up a girl at a club. She's not that type n I know she doesnt drink n go to clubs. I'm also not looking to loose my family over this either.
Well, we had eye contact a few times n noticed something. She started to talk to me about business and we scheduled to eat lunch together, business but I felt something else. Then we met at a small, group of 7, business meeting/lunch. Sat together again and shared our food. I know this is nothing, but things keep just happening with her. Like these are business meetings n end up seating together n sharing our food. Like when I needed a ride home cuz my wife couldnt n this girl happened to be at the parking lot n she game a ride home. The 3rd is at a business after hours event, which my wife went with me n she was there. Thats how she met my wife, but the whole time, she avoided to meet my wife. Both my wife n me noticed that she was very uncomfortable with it. This is a girl thats very hot, a 10 in my mind, n very very outgoing. So, I was worried that her n my wife would become good friends n I was wrong, she could not be herself at all. All this was that what led me to feel that something might be there even though she knows Im married. So thats when I started to get interested n that I was going to try to invite her to things n see how she reacted. The 4th was on a 3 hour training meeting at night that she was late 2 HOURS, but I felt she went there looking for me cuz she was there almost at the end, no use at that point to show up if she went there for training. She sat next to me n thats went she told me she had a very rough day n look very down. I asked if she wanted to go get a coffee or something so we talk about it. She accepted and thats when she told me she was broken hearted n crying. That she has been in n out of a relationship, but waiting for him. She also gave me mixed signals by telling me that she doesn't mess around and only looks for marrige material. We talked till midnit that night. Because of the situation, I did not wanted to take advantage of her feelings n make a move then. I just listened n gave her advice. A few days later, at a meeting, she was like nothing a avoided to talk to me. I called her a few days later to ask her if it was ok for to just call her to invite her to things. At first she said it was ok n then she said she was going to think about it because "she was in tender moments right now". I said we'll talk later about it. 2 weeks later, I saw her at a meeting n she said she was going to call me. She didn't. I texted her that day to ask her out n she accepted. So we went out this past Sat. nit (a week from today). This the only real date we have had. I have been trying to advance things; so we went to a play/show n took taxi there, took advantage to get a limo back to our cars n drank some champange. later to a restaurant n walked to her car n she drove me home. She looked ok with everything but I just couldnt get the conversation to a romantic level. She talks too much! I also feel that she was hiding behind her talkative self so she can keep things in the comfort level n waiting for me to make a move n I couldnt.
After all that, I just could not see a chance to get very close. She seamed too inocent! Thru all this, she knows Im married and doesnt ask about my current situation at all. My question is, should I have been more agressive or what? Do you think that I lost my chance? what do you think is going thru her head as far what Im looking for since Im married? Do you think Im in the best friend zone or thats a good thing in my situtation for now?
My last contact with her was that sat nit when we went out and drove me home. We left it as that she was going to invite me somewhere, but don't know when. At the end, I said I'll see you...well dont know when since we dont have a meeting next week cuz of the holidays so next meeting is till Dec3. She said, well...have a great thxsgiving. So we said bye, a hug n thats it. Since it has been 3 days already, I texted her on (this past Tues) telling her that I wanted to see her b4 thxsgiving, n that till next meeting was too long. Possibly tomm after work so I can take her to a happy hour to a place we talked about. I even texted something that I know she will laugh about. She never replied. Last thursday when I invited her for sat. she replied in 2 minutes.

Need some advise as how to take it from here and how often should I text/call her or not.

Thanks! Rico