My relationship with my mother is severed and she doesnt know why.

I found out that she is going out with someone and has not told me about it- my parents divorced 8 years ago. I have repeatedly told her that it was okay for her to find someone and move on. After years of fake crocodile tears and telling me that she is alone in life and will probs die alone- have felt guilty and responsible, about 3 yrs ago saw a message on her phone with this guy since then about 5+ years and had to lied to me out. I feel so betrayed, and am frankly jealous that she lied to me for so long, all those "meetings", and the times she had to go to the library, or religious meetings or go to yoga lessons were a lie. I feel so emottionally drained, my father is not reliable either... Feel like i can't trust anyone...