Hello guys,
I've been lurking for a while and decided to make an account cos I have some info about that website our dear David is using. Or rather, my wife has (she's Russian and yes we met online lololol - I'm French btw).
Anyway, because she teaches english, a few years ago she was contacted to work for the Anasthasia dating website (not sure of the name, but definitely the one we see on the show), so here's how it works:
Girls have to make a real profile, and beside that they have to manage 4 other fake accounts.
Obviously David has been dating a fake profile for 7 years now. It's probably several persons shared the Lana account given how long it's been.
The "1 real profile" thing also explains how he made that Ukrainian friend who feels so sorry for him.
Maybe some men manage accounts too, it could be possible. I don't know all the ins and out since my wife only did an online interview and refused as she was only interested in doing translations.