In love with my best friend...

Firstly, I would like to apologise, as I expect this is going to turn into a bit of an essay but I feel it's important that I get all the details in,to show the true picture of what is happening (and also, I am probably using this space as a bit of a vent)....It all started about 6 months ago, when Helen joined my place of work, I noticed she was Gay from the first moment I saw her and thought instantly that I wanted to get to know her. At the time I was one year into my civil partnership with Aimee. Anyway, Helen and I worked with eachother a few times and really got on, after a while we became pretty much inseperable at work and it didn't take long for me to start having feelings for her. Because of this (and amongst many other things) I ended my relationship with Aimee. On a drunken night out, with Helen and her girlfriend (who, by the way, at this point, Helen had told me she was very happy with) I very stupidly told Helen that I had feelings for her, her response at the time "Don't ruin our friendship, I'm happy with Hannah". After that, we seemed to get closer and closer, both of us spending as much time as possible together at work and sometimes evenings together at her house. There was definitely a lot of flirting and sexual inuendo and then one night when I stayed at her house we were cuddling (as we did) and she told me that there was something more than friends there for her too. After that we've spent many times discussing our feelings for one another and have even tried not being friends at all to make it easier but we could never get through a day and both of us ended up in tears. One drunken night, we ended up sleeping together and after that I was convinced that she would finish with her girlfriend but never did. She has told me that things have changed between her and her GF and she wants to see if she can get things back to how they were with her but at the same time still wants me as a friend...She tends to give out really mixed signals and definitely indicates that there could possibly be some hope for us in the future, only last week she told me to listen to the song "here we are" by Gloria Estefan, which really messed with my head...So basically, my current situation is this, I am completely in love with her, she has a girlfriend but I'm pretty sure she has feelings for me, I see her every day at work, where we generally spend most of the 8 hours together, she's my best friend but every day it is killing me that I can't be with her and she's with someone else. I wish I could fall out of love but don't know how and not being her friend is not an option and there's a huge part of me that just wants to wait to see if it does eventually happen between us, so, as you can tell, I'm really confused and don't know what to do for the best, any advice would be greatfully recieved...Thank you