What’d I Do?
Moving in together entails more contact, and sometimes more communication equals more friction. When you argue, you want to be in your comfort zone, but when things get out of hand, you don’t care who is at fault. Someone has to give in eventually, and someone has to accept responsibility. You’re sick of the Cold War already and want it to end.
Even if you believe your anger is merited, your girlfriend may accuse you of behaviors that you were not aware of. Perhaps you don’t have to apologize as quickly as this individual did, but apologies are still required. If you’re not ready to apologize, be prepared to forgo a few decent times with your buddy.