Do you think it's wrong for a married couple to record themselves on video when having sex?
The question that must be asked is, "For what purpose?" Why would a couple want to record private moments, especially given that it may be seen by others? The only reason that I could come up with is that a couple involved in recording their sexual acts are interested in producing their own private pornography.
"Therefore, since Christ suffered for us in the flesh, arm yourselves also with the same mind, for he who has suffered in the flesh has ceased from sin, that he no longer should live the rest of his time in the flesh for the lusts of men, but for the will of God. For we have spent enough of our past lifetime in doing the will of the Gentiles--when we walked in lewdness, lusts, drunkenness, revelries, drinking parties, and abominable idolatries" (I Peter 4:1-3).
In the above verse, "lewdness" is from the Greek word aselgeia, which means licentiousness or shamelessness. It basically refers to people who have no moral restraint, but act as animals, focused on their own self-pleasure. "Lusts" is from the Greek word epithumia, which means a strong desire, especially for that which is forbidden. It would seem to me that recording acts of sex is a focus on worldliness and sensuality. Married couples ought to find pleasure in each other's body. "Let the husband render to his wife the affection due her, and likewise also the wife to her husband. The wife does not have authority over her own body, but the husband does. And likewise the husband does not have authority over his own body, but the wife does" (I Corinthians 7:3-4). But recording it is to put those private moments on display, making the focus purely on the lustful passions that it produces.
During Israel's downfall, God asks, "Were they ashamed when they had committed abomination? No! They were not at all ashamed; nor did they know how to blush. Therefore they shall fall among those who fall; at the time I punish them, they shall be cast down," says the LORD" (Jeremiah 6:15). The people had become so immune to sin that they no longer blushed when confronted with it. I fear that we have done the same thing. Movies, television shows, books, and music all put sexual acts on display, causing society to be desensitized to it. Recording sex is not romantic, it is cheapening of a special moment. You might as well invite others into the bedroom.