Many therapists believe that couples should not make a big deal about masturbation as it is so common place.
If the two of you can communicate your needs and desires with one another and accept that masturbation is natural and okay, masturbation should not be a problem in your marriage.
More Questions/Answers About Masturbation and Marriage:
What is Masturbation?Masturbation Statistics -- Who Masturbates?
Why Does My Spouse Masturbate?
What About the Moral Issue Concerning Masturbation?
What are Some of the Myths About Masturbation?

