David Martinsson From Viral 'Being Ugly' Video Only Cares About Wife's Opinion

David Martinsson went viral for posting a video about "being ugly" ... but it led to him meeting his wife and having a child, and now he says her opinion is all that matters.

The YouTuber and his wife, Juli, joined us on "TMZ Live" Friday and we asked him what led him to post his now viral video.

David says at the time, 8 years ago, he'd been single for over a year and didn't have a lot of people he could talk to about his feelings ... and he posted the video thinking it would disappear into the ether.

The opposite happened ... his clip has 26 million views and counting. Among those who saw it was Juli, and we asked her what she found attractive about David.

They're now married with a kid ... and David says it's changed how he views himself.