Apparently she did ask that question out of insecurity. G is getting better about dealing with it, and I think she understands that L gives me something that G cannot, nor would I want her to.
Lately, L has been going through some pretty deep and shockingly difficult spiritual things (G and I both practice what most would call Magic though in different ways), and G has been very sensitive to it, and supportive. She even asks to make sure L is ok after I talk with her - I think she's beginning to feel empathy for L because she knows I love her, and when she hurts, it hurts me. It's hard to see L going through something like this, and being basically unable to do anything to stop it. I help in what ways I can, of course, and I need to go to her and see her soon. G was understanding about me needing to see her last time, and the result of our conversations has been very positive. She's been communicating a lot more (and was more insecure than I realized), but is doing better every day. She's even mentioned dating a few times, and sex between us has been good.
I talked before about seeing the three adult owls living together... Today, G saw three adult doves together in the yard, and mentioned it quite specifically to me. The effort she's putting forth to love and support me even though it's hard for her just makes me love her even more with every passing day, and L is the kind of woman that makes me want to be a better man, a better husband, and a better father. The radiant love and positivity in my life right now is unbelievable, and with a foundation like this, I feel very confident that together, we can handle anything that comes our way.