You don't give much to go on. Like the things you have tried. How she reacts to you in your daily like. Conversations would help us out to try and see where she is coming from. But mostly things you have tried to do to turn this situation around. You never comment much on that. So based on so little to go and all I really know is that your wife avoids sex to no ends with you.
Well, maybe she doesn't enjoy sex with you. Perhaps you can't get her to orgasm. Maybe she is just not attracted. So she fills her life with other voids to try to make up for it. Maybe she is feeling like she will never have a sexual partner she can click with.