It's in most people's nature to put off things they don't want to do. However, you should apologize sooner rather than later. If you wait, your guy is only going to get angrier or more hurt. Don't try to apologize when your guy is sitting down to a football game or reading a good book. Choose a time when he's not distracted by something else, and ask if you can talk. If he already knows what you've done, he probably can guess what the conversation will be about. If you need to confess, it might not be as easy for him to guess. That means that you convey with your tone and attitude that you are sincerely sorry for what you did. Don't try to laugh it away, or play it off with a joke. Look him in the eye, and with a serious tone, say you're sorry. For instance, you could say, "I'm truly, truly sorry about what I did." Also, you need to accept that what you did was wrong in the presence of your guy. That means naming what you did wrong to acknowledge that you know what you did. As an example, you could say, "I know that when I made a joke at your expense I hurt your feelings. I should've thought before I spoke. I know you're sensitive about that issue." Finally, you have to acknowledge how you could do better in the future. This part is how you start to make the situation better. You can't take back what you did, but you can talk about how you intend to change your behavior in the future. As the end of the apology, you could say, "Next time, I'll try to bite my tongue before I speak. You deserve better from me. I love and respect you, and I want to show you that with my actions." If this conversation is the first he's heard about it, he's probably going to be angry. Let him give voice to his anger, but don't try to offer a defense. He needs a chance to talk about it. Even if he did know about what you're apologizing about, he still needs a chance to talk about what he's feeling and why. Give him an opportunity to speak about why what you did hurt him. You can give him a space to talk by saying, "How do you feel...

How would you rephrase that briefly using Indonesian?
Janganlah tunda permintaan maaf. Pilihlah waktu yang tepat. Tunjukkan rasa bersalah. Bertanggungjawablah. Katakanlah bagaimana Anda akan menjadi lebih baik. Biarkanlah dia merespons. Akuilah perasaannya.