If you intend to continue having sex with their daughter, don't apologize. Wait them out and in the meantime be respectful if you are around them. If you don't intend to continue having sex with their daughter, then say something to the affect of "I apologize for not showing you or your daughter the respect you deserve. Please know that I am sorry for my actions, and will show nothing but the utmost regard and respect for your daughter and yourselves in the future. I hope to prove to your daughter that I am capable of caring for her deeply without expecting her to compromise her values, and of remaining a gentleman in any way that I can be. Thank you for your consideration and understanding."
You could also use this even if you intend to continue having sex, and just be WAY more discrete..never put anything into text, email, paper, journals, photos, or audio/video.
Good luck and best wishes. Oh, and use birth control! Please!
