7/ Learn how to apologize, and how to forgive
It’s a very important thing in a long-term relationship! You must learn to say you’re sorry. Admitting your mistakes is way more important, and you can move on faster than if you hold your ground indefinitely. And better late than never! And don’t even think that it’s not worth the trouble because it happened last week/month.
When you apologize, make sure you want to, and be sincere. Otherwise there’s absolutely no point. In the same way, when your sweetheart comes to you to ask for your forgiveness because of her attitude, forgive him/her! And the both of you can swiftly move on. The past belongs to the past, don’t let hard feelings poison your lives.