read your entire blog.
You can read some of what my life is like as well.
Here is what i have to say. I love my wife more than she will ever know, I will be with her right to the end. I also love my GF, and i know my wife loves her BF.
I see her the way she lights up sometimes when she sees him. She does not do that with me anymore, but thats OK, yes it hurts me a bit, but I know we have a strong love for each other. when she is happy with him I am really happy for her.
Yes there are times i can be jealous, and i give certain things to my wife that she doesnt get from her BF and vice versa. And you know thats good, it allows for all of us to grow and learn.
If you take khas out of the picture , how would you feel about B? thats what you need to concentrate on, and yes you need to feel good about you.
As for him not loving you best, thats probably not true, as it is for me, i love my GF and that DOES NOT take away from the love i have for my wife, although those loves are quite different.
Instead of khas always being away from you , this has the negative of making you feel alone, perhaps they should spend time together with you. It is ok for you to see the love he has for her, take joy in that and you will find that things will be better. when he gives that love to her, its not like he is draining the love pot, so there is none left for you; far from it, also know that down the road the new love will settle down to be a more regular love as well.
enough of my ramblings. If you can take joy in what they have it will help you, but you are probably feeling alone right now and that is more than likely damaging your feelings.