moved on but sometimes it still hurts

my ex girlfriend cheated on me and today her and her boyfriend (the guy she cheated on me with) made one year. im happy for them, i just hate how she gets to live her life in a happy relationship while i fear commitment, but still try. i’m over her, but sometimes i just ask myself what he gave her that i didn’t. everyone deserve happiness, i just wish she knew how i felt when she cheated.