Can you remain faithful to your partner if you are in love with another?

About 8 months ago a new woman started at the organization I work with. Just about at first sight, I fell in love with her. We worked together on a few jobs with other coworkers but I never really got close enough to her to get to know her. Then, one day we worked alone together on a job and we just plain clicked. We got to know each other a bit, enjoyed our time together, and left the job just feeling like we had both created a new bond between us. At the time, she was married but going through some issues with her husband being a jerk and abusive. She has since found out he was also cheating on her and that was the last straw, she initiated divorce proceedings and feels that he (her 3rd husband) may have ruined it for any really nice guy out there. She's pretty much had it. I have been in a relationship with another woman for about 10 years now. We got together out of mutual attraction, and we have built a love and a bond between us, but we were never "in love" and I am not "in love" with her. We have built a great life together and we get along, for the most part, pretty well. I was a rebound relationship for her after her husband died due to a medical issue. She is selfish, respects nothing I have to say - until it proves to have been right, but all other times "she is right". Our relationship is not perfect by any means but it has been stable and we do have a general respect for each other. They say opposites attract, she is essentially my identical twin. So here I am, I have a great life with one woman. A nice house, animals, a steady, reliable relationship that has proven the test of time. Another woman, however, owns my heart. She is in my mind both when I am asleep and when I am awake. When she has not responded to a text message for a day or two or when she is not nearby or when I do not know she is in a safe place I physically get queasy in my stomach like there is a big empty hole. In that place between sleep and consciousness I found myself writing her a love letter, something I haven't done for about 40 years. I sent her a text message early the other day asking how she was holding up and then spent the rest of the day hiding from my phone and in a state of depression because I couldn't bear having my phone with me and not getting a reply. (she replied to the text within 30 minutes from my having sent it, but I didn't see it until much later in the day. It included an invitation for me to come visit with her.) Questions: Have I already cheated on my current partner? My coworker and I have not as much as held hands at this point. Am I being unfaithful to my current partner? Is this feeling of being "in love" (infatuation?) somehow equivalent to being unfaithful? I don't know that the relationship with the coworker will, or will not, go anywhere. I intend to explore that more during a lunch date I have set up with her to find out her intentions and to tell her more about me as, at this point, she really doesn't know that much about me. That may end the relationship right there. But my love for her will probably still live on, at least for a time. If she wants to move forward, I may submit; I haven't felt these feelings for many years and they don't come that often in life. I would be throwing everything away. We (she and I) would have to start over from the beginning. - That too may end her interest, it may be my current status in life that is a major point she is attracted to; still my love will live on, for a time.

I'm not currently married. My current relationship is much more like being roomates than having an intimate relationship. We sleep in the same bed, share the bills, and share responsibility in life but that's about it. I think I know why I'm "being distracted".

1. NOT MARRIED!!! 2. Our relationship was pretty much over long ago. We are at a place where we are just using each other for financial reasons at this point. That said, we have a very comfortable life together and I have no desire to hurt her. Yes, I want to explore this new option. I just want to do it "right", if there is a "right" way to do it. I also don't want to destroy the life I have until I'm sure I want to move on. When it's time to move on, to tell her I have found someone new, I want to do that as sensitively as possible. To tell her NOW that there is someone else would be premature. So, how do I explore this new option without crossing the line? And, I'm not talking about sex. She and I have been in a sexless relationship for years; I think I could go a few months longer. My primary interest here is really to minimize the pain for her and the risk of making a bad decision for me, if either of these goals are possible.

You want to do it right by you? Or right by her? Doing the right thing by her would be to tell her everything you've written here. Leave your comfortable but unsatisfying relationship and then take this new risk with a clear conscience and a hopeful attitude. Even if that might be difficult for you. Doing right by you depends on your conscience and what kind of person you are. Just for the sake of argument obviously the most extreme level of selfishness would be to start a new relationship and wait until it's a certainty before ditching the old one. It sounds a bit like you're asking for permission to do something you believe is wrong. The only person who can really give you permission is yourself. Just comes down to your conscience in the end. One piece of advice I can give to you is it might be more helpful to think about what is the most respectful way to treat your current girlfriend rather than the least hurtful. It'll hurt her no matter what.

@Tired... Yeah, spot on. And, well that really sucks! I'd like to address this though "Just for the sake of argument obviously the most extreme level of selfishness would be to start a new relationship and wait until it's a certainty before ditching the old one." Don't I owe myself just a little bit of "selfishness" here? I certainly don't need to go to the point of certainty with the new relationship but shouldn't I at least confirm "possibility"? I'm thinking it would be just plain stupid to throw my current relationship away based on a pipe dream or, perhaps, a mid-life crisis. And, I have to say, based on the level of selfishness I've had to endure from her over the last 10 years my conscience is pretty clear on watching out for my butt a little bit here.