@s m e l l,
Partner is an un-usual term for someone young so I am going to assume you are not young.
Sorry would be the first word. And, then count your loses if you did something un-toward to the relationship.. You can't take back something that should not have been within a relationship not even words, you can correct a mistake but if it's infedility? Then na.
If you used words to hurt him? And that upset him, words are usually true..in the heat of the moment so why backtrack?
And, if you said something about family, same thing.
You can't back track.
If you are in-fact young and used the word "partner" ask what you did, was it really wrong? Or were you being you... And, if it was wrong, then again wear it.. put it down to lessons learnt.