Note: Emo post. Read at your own risk.
I haven’t been into many relationships. And I’m clearly not an expert on such matters. But the earliest and the most precious lesson I learned about relationships is about respect.
Relationships are based on mutual respect for each other. And when you lose that respect; either for your partner, or yourself; even if you love each other, the relationship will crumble.
The only way to repair it is to restore that lost respect to your partner, or to yourself.