Cheating and lying :couples must share the blame

In a relationship for four years which has had many problems related to trust and respect , have broken up many times and gotten back not because of cheating but because we couldn,t find common goals , ways of communicating and meeting each other,s needs. Very controlling, critical guy and me unable to assert my needs. Finally broke up and I decided to go out with a friend ( guy ) to a concert. Starting seeing my ex again before the event and it was overall good but as he ramped up the controlling behavior, I decided I was afraid to tell him about the concert. Couldn,t go out with friends alone, always checking in on my whereabouts, was being accused of too much drinking etc... I lied to him about the concert but by morning decided to tell him. He has responsbility in this as well but isn,t willing to acknowledge it . There was no way he would have agreed to my actions which were not romantic at all! This lying act was a result of the failures of the relationship no trust , no respect not that I am an evil person who has no moral sense . I feel shame but also compassion for myself . I am realizing that its not fair to accept full responsibility for this failed relationship . It was a ship taking in water before it hit the iceberg anyway . If you can,t trust your partner to tell them the hard things and they aren,t worthy of your trust because they cannot hear your point of view or have compassion for you , and don,t respect you as a person, then the blame has to be shared .