Your wife appears to be asking you to gain more sexual knowledge. I am editing this because in an attempt to be funny and generate a conversation that lets you kind of open up and explore your options, I did a poor job of achieving that goal.
I personally do not think sex outside of marriage is a good idea, nor is that a DB tenet, and I seem to have made the statement that it's ok. My point in trying to be funny is that I know that some folks do agree to an open marriage, and I think it usually goes poorly, but it if was your choice, I was trying to help you be creative with a solution. I apologize.
There are ways of obtaining more expertise without having sex outside marriage.
The two I was able to think of are in the post that follow.
