Bob and Jane were married 25 years. When they first got married Bob said, "I am putting a box under the bed. You must promise never to look in it."
In all their 25 years of marriage Jane never looked. However, on the afternoon of their 25th anniversary curiosity got the best of her and she lifted the lid and peeked inside. In the box were 3 empty beer cans and $1371.75 in cash. She closed the box and put it back under the bed. Now that she knew what was in the box, she was doubly curious as to why.
That evening they were out for a special dinner. After dinner Jane could no longer contain her curiosity and she confessed, saying, "I am so sorry. For all these years I kept my promise and never looked into the box under our bed. However today the temptation was too much and I gave in. But now I need to know why do you keep the empty cans in the box?"
Bob thought for a while and said, "I guess after all these years you deserve to know the truth. Whenever I was unfaithful to you I put an empty beer can in the box under the bed to remind myself not to do it again."
Jane was shocked, but said, "I am very disappointed and saddened but I guess after all those years away from home on the road, temptation does happen and I guess that 3 times is not that bad considering the years."
They hugged and made their peace. A little while later Jane asked Bob, "Why do you have all that money in the box?" Bob answered, "Whenever the box filled with empties, I cashed them in."