You are allowed to leave, to turn and walk away, never to look back. If it is that bad, if it hurts that much, if there is no redemption possible, no reconciliation possible, it is okay to leave.
You are allowed to withdraw from abusive people, to depart from unwholesome people, to escape another betrayal.
You are allowed to say ‘no’ without explaining why. Say ‘fuck, no’; it is okay. You are allowed to quit something you detest. You need not offer an excuse. Break a promise, break a contract; you cannot be held captive to something you despise.
You are allowed to start over. Starting over does not necessarily mean that you failed. If you did, you are free to try again, and again, and again. But, maybe, you are starting over simply because to want a better start.
You will never have any real, legitimate power or control over anything else, or anyone else. Only your choices are within your command.
You are allowed to make you own choices.