If the disrespect was so bad that it led to you breaking up then consider yourself lucky it happened sooner rather than later because it tells you a lot about a person and/or your compatibility.
If you acted unreasonably however, then the guilt may have merit. Women are more resilient than they appear in such situations and always, always having apparent mental fragilities or dealing with a lot at the same time - which helps your guilt really burn your soul even more. You care for her after all and don't want to be a source of pain.
You say you don't regret it which means you don't believe you were unreasonable.
Was it really this act of disrespect or was this a good opportunity to end something you didn't truly want anyway?
You may have to tell us the full story and provide a full body pic of her for more accurate advice.