Never let him forget
Okay, so he forgot your birthday, but you decided to stay with him so it’s time to forgive and forget. Girls cause break-ups because they hold wrongs their boyfriends have done against them and every time they do something wrong remind them of their previous history. If you can’t get over the way they treated you then it’s time to end it. If you can forgive them and don’t want to cause a break-up try to let the wounds heal and don’t always throw his wrong-doings back in his face.