“I am sorry, but you also…” quickly turns an apology into an accusation.

“I am sorry, but you also…” quickly turns an apology into an accusation. The listener hears defense instead of responsibility. First own your part without conditions: what you did and its impact. The other issue can be discussed separately. A sincere apology does not try to win the argument in the same sentence. It puts down the weapon and attends to the hurt caused.