Fell in love with another woman

I have been married for 15 years now and have three children. For the last several years our marriage has become nothing short of a business like relationship with the kids being the product. Sure we do family stuff, but as far as my wife and I we don't sleep in the same bed and haven't had sex in literally years. The reason is mostly frustration due to money, sensitivity and being miserable. Recently (about 6 months ago) I started a job at a co. in my industry in which I was reunited with someone that I was always attracted to but had not seen in 4yrs.Since day 1 that she realized I was with the co. she clinged to me for the simple reason of I was an old friend from a previous job and she was unhappy at work and needed an old familair face to vent to and compare previous co.work to, etc.She is single with a daughter from a marriage that went bad. Her ex recently passed away which brought her and I closer because even though I was a work friend I felt like I was there for her. She and I are 'work friends', but we are pretty good friends to the point where I'm sure we fall into each other's top 4 or 5 closest people whom we talk to and converse with.To paint a better picture we literally spend all day together in some fashion either going for coffee, sitting together at lunch, going for walks during nicer weather & emailing each other daily on work emails to an avg of 40 emails a day. Wonder how we are even working.now there's a few things that need to be outlined here: I don't text. If I did we would prob text each other outside of the office, but instead resort to a handful of emails at home on our personal email. She is very tall, thin and beautiful. I'm short,very overweight & not very handsome. Together we are very honest with each other as friends, yet respectful, sensitive and sincere. I care very much for her and have fallen in love with her not just because of her exterior beauty, but of who is she and things she does. The thing is that I truly believe I am nothing more to her than an old work friend who wound up at the same co. as her and she can count on. I'm not sure she even sees any sexuality in me whatsoever since 95% of the time we spend together is at work meaning that I could be a man or woman and it doesn't matter.I constantly compliment her, treat her nicely, buy her coffee every morning and we are very close..but I've fallen in love and not sure what to do.