Self-respect is learning when explanation starts becoming begging.

There is a point in explaining yourself where the purpose changes. You start out offering understanding, which is generous, and at some stage you are asking for permission, which is not the same thing. The tell is usually in the repetition. Once you are saying the same reason a third time in different words, you have stopped informing and started pleading for agreement you do not need.

Say it once, clearly, and let it stand. If the person still disagrees, that can simply be a disagreement rather than an unfinished argument. Practise ending a sentence and not filling the silence that follows, because that silence is where most over explanation happens.