When someone quarrels with you trying to blame you, they'll always talk about the bad things you made. And never they thought about what you did good to them.

When he/she is at wrong, he/she knows he/she can't debate back. That's when all the wrong things you'd made/accidentaly happend will burst out from thier mind. Unrelavant things that's not apart of the actual debate will come flowing at you. Making you debating about the past and making the relationship worst.

When you know you're in the wrong, give it up. Do not include the past . Past are past . You were quiet about it since then. And suddenly you have to bring it all up, just because you had nothing to quarrel back.