My longest record 48 hours. We are together for 6 years now, a tiny tip is look at your bf or gf like a spoil little boy/girl that need to be pamper and sometimes kindly point out their bad behaviour in a strict way. I try to understand what he was angry about and admit my weakness( pride can be harmful to the relationship) and i point out what i hate about him without accusing. Guys can be defensive when they thought you are accusing or condemning them. Well, take everything with a sense of humor if you want to grow together. Kevin Bacon (actor) once said to he maintain his relationship with his wife through this motto:
'Keep the fight clean and the sex dirty'

Clean fight means not to drag out topics that suppose to be cleared a long time already ( i think some girls always use this weapon when they want to win).