I used to have a coworker who had a wife and 3 kids. He and his wife combined weren't taking home much more than I was by myself. He and I would eat lunch together every couple of weeks or so and most times I would pay for both of us. He'd always say no but I'd pay anyway.
That being said, I may try to find them anyway. The last time I saw them was at his wedding 9-10 years ago.