Article: Look him in the eyes and say “I’m sorry,” and paraphrase what you are sorry for. It's important that you make clear that you understand exactly how you've hurt him. Including what happened will let him know you listened and considered his thoughts. For example, if you're apologizing for yelling at your boyfriend for something you knew wasn't his fault, you might say, "I'm sorry I lashed out at you last night over something you had no responsibility for. I understand how this made you feel like I didn't care about your feelings and was just using you to selfishly take out my anger." Instead of including a reason that you would have behaved this way, you should refrain from giving your feelings on the situation immediately. Giving excuses for your behavior will make it sound like you're not really sorry.  For example, instead of saying, "I'm sorry I acted the way I did. I was just really frustrated with things at work and I had a headache that was making me cranky," you should just say, "I'm sorry I acted the way I did. I had no right to be like that to you." If he wants to know why you acted the way you did, he can ask you. Then, you can explain your behavior. Insincere apologies often express a regret for being caught, rather than actual remorse. For example, saying “I understand it will be hard to trust me” will help him to understand that you have considered how your actions affect him. It's wise to let him know you don't expect immediate and total forgiveness. Cut down everything you want to say to short, straightforward statements. Get your remorse, understanding, and acknowledgment across without going on to much. This will both give him more time to let out what he needs to say, and avoid any sort of miscommunication

What is a summary?
Express regret and remorse. Take full responsibility for your actions. Acknowledge repercussions, if there are any. Keep it short.