He lied to his wife, but why?

[K]

I had a question a couple weeks ago about my friend's dad (42..I'm 19) where I got 38 answers saying he's sexually attracted to me.

I have another question: me, him, and his wife play a Facebook game called "Nightclub City." A couple months ago, he started "buying" me drinks on there. At first I was weirded out, but I just figured it's a game so it doesn't matter. After some time, he kept "buying" me more drinks and eventually started "winking" at me on there. We've been going back and forth with it for months now and he's even gone as far as 23 notifications on there.

Today, I was over at their house and his wife was sitting there waiting to get online. For some reason, he was checking his Nightclub City when she was right there. It seems that was the first time she ever saw the notifications I left him, even though we've been doing it for months. I acted like I wasn't paying attention, but I heard him tell her that I send them to him, so he just sends them back and he jokingly referred to me as an "alcoholic" LOL.

Anyways, why do you think he lied? He's the one who started sending them to me and even sent the first "wink" to me.
JoGusto-No, definitely 19. I guess I know the answer, but I just wanted others' opinion. Think about it, don't most people on here know the answer to their questions, but ask them anyway?
For the record, their marriage is really bad. They argue all the time and she rarely gives him "any". The wife is very open with me and her daughter about their marriage. Point is, they're not happy together, but they stay together for the kids.