I don't think the person telling the story lied to cover up his habit of gambling, his wife may have known about him gambling but what she didn't know was that he considered gambling the favorite part of his day and not the time spent with her. Telling the wife the truth that whenever he gambled was the best time of his day is a statement capable of ending the marriage. He is a chronically addicted gambler who does not want his partner to know how addicted he is to gambling, and an adicted gambler who will not easily change.
This is why is good to be opened with your partner. When you communicate with them do not use words that are ambiguous that even when they do not understand, they cannot ask you what it means exactly. I think that he may not have told his wife directly that the favourite part of his day was gambling and it is not good because someday when they have a very heated argument, he would go on to blurt it out.
And how do we think it will make her feel. I think that we should all avoid any conversation that can put in in this position where we neither lie and can't tell our partners the truth. Since he is good at hiding his addiction, he should go get some secret therapy such that before his wife knows what's happening, his gambling will be under control.