They are taking what they want where they can get it instead of where God designed your sexual energy to be focused at (a man’s wife).
1 Timothy -19 – Timothy, my son, I am giving you this command in keeping with the prophecies once made about you, so that by recalling them you may fight the battle well, holding on to faith and a good conscience, which some have rejected and so have suffered shipwreck with regard to the faith.1 Thessalonians 4:3-5 – It is God’s will that you should be sanctified: that you should avoid sexual immorality; that each of you should learn to control your own body in a way that is holy and honorable, not in passionate lust like the pagans, who do not know God; And a call to control yourself, to not be overtaken by passionate lusts.
But, now let’s look at some masturbation stats: A survey of 600 Christian men by Dr.
Archibald Hart revealed: At a poll at The Marriage Bed forums, over half the men said they were having sex with their spouse once a week or less. Achibald Hart, we see 61% of Married Christian Men masturbate (wives, take a look at your husband, over 50/50 chance), and only 13% of them feel it is normal.
Talk to your spouse about it, see if you are harming them by masturbating.
If your spouse doesn’t know, then I submit that you are lying to them by not telling them part of your sexual activity.
But, I think the largest argument is not an explicit verse, but rather the overriding message of the Bible with regard to marriage and sexuality.