So a proposition of an affair?

Ok, so I was wondering how many people out there have been propositioned by someone wanting to have an affair. You see yesterday I was at work and this guy that works there that is 26 and married (I've met his wife) asked me out! I was a bit shocked because I'm only 17. Anyway has anyone ever flat out asked you to have an affair with them even when you've met and talked to his/ her spouse?