relinquished that right upon breakup

Why do ex’s feel that they have the right to decide whether or not they can be a part of your life again? Didn’t someone tell them that they relinquished that right upon breakup?

So maybe that needs a little more clarification, but I’m not feeling charitable, suffice to say that it was someone that strung me along in the semblance of a relationship while really just using me for attention and screwing around on me on the side. I felt hurt, used and betrayed at the end of it. For reference, see whichever previous valentine’s day involved chocolate cheesecake. Sometimes I forgive and forget, most times I just forgive, this is one instance that I just tried to forget as forgiveness isn’t an option unless I become a priest.