Al Robertson, son of Duck Dynasty's Phil Robertson and Miss Kay, opened up about one of the most difficult moments in his marriage - and why he decided to stay and work through it. In an interview for their upcoming documentary Faith & Forgiveness, Al revealed how his wife Lisa Robertson's infidelity, which occurred 15 years into their marriage, brought the couple closer together rather than tearing them apart. "I think the reason I was willing to fight for my marriage was that I had made a lot of mistakes on my own," Al admitted.