She's single because her ex never valued communication and her feelings were neglected. Sex wasn't good anymore because she lost feelings for the man who gained feelings for another female. Trust became an issue because she was lied to, cheated on, and disrespected. Getting jealous became a habit because another female was receiving his attention, time, effort, and care. She's not single because something is wrong with her. She's single because she cared too much for a man who didn't love her and couldn't commit.