Well, it might still be jealousy. My point was that you don't feel that with me because you know I love you, and this got us closer. With J, you've had feelings for her for months, you asked her out and she said no, and since then she's been actively looking for someone, so you can't even tell yourself she doesn't want a relationship right now. It makes the rejection worse I'm sure.
I think it's natural to feel bad and sad about it, although that doesn't mean you are any less of a person. I am with you, I married you and I love you, I know how wonderful you are. Similarly, there are many people you know and think are great but wouldn't want to start a relationship with.
I think J sees you as a coworker and friend, and is a bit weirded out by our relationship dynamics, but that's all about her and not about you. When it didn't turn out with my interest, I know I could fall back on the certitude that there was nothing wrong with me, because two wonderful men love me, and that it was just the way things were that he wasn't interested, that a relationship wasn't going to happen.
I think it would help for you to remember that I love you and that I'm a wonderful person with great taste, right?
So obviously J's just missing out.