I confronted her with my suspicion and she told me she lied about him riding with her.
Have you asked her why she lying constantly?
A person who is doing nothing wrong doesn't really need to hide anything.
I can't tolerate lying, personally in my own situation, it made me sick to my stomach, that's when I started losing respect for my W. If you have respect for yourself, you won't tolerate people who lie to you.
Let them go, move forward with your own life, detach, have a great life and start limiting your interaction with her.
