Unfortunately this is not a matter to be taken lightly as I’m sure your husband knows. I have only recently rid myself (for the most part) of this sin. As I have been where he is now and I think I may be beating this I think I can offer a little help.
First and foremost he must know that masturbation is a mortal sin and a direct attack on his soul. I wasn’t aware of this fact for long after I became addicted but it was a major wake up call to me when this fact really sunk in.
Second he must know that the temptation will never go away. This is probably one of the most despairing realizations I had, that even though I think with prayer and perseverance it gets easier, it never goes away. My father once told me that a young seminarian once asked an elderly priest when the temptations go away, to which the priest replied “About three hours after your dead.”
Another main thing is that unfortunately there is no magic technique or pill to make this any easier, we must carry this cross as best we can, now he won’t become perfect I’m sure even priests fall to this type of sin occasionally. What matters is that when you fall you must get up and try again with renewed determination. God never asks us to do something that we are incapable of, and He knows our limits far better then we do.
Pray, that’s the main thing that got me started in the right direction, pray the Rosary (together would be even better) and also in general to the Blessed Mother for grace in abundance to overcome this sin.
Go to confession… often. The graces received at confession helped me a great deal.
Avoid the occasion of sin, (this ones a biggie). Have him sit down and write out what leads him into sin, is it the television, the internet, in the mornings, the afternoons whatever. If these things are avoidable, then avoid them if not (and if it is a place) he should surround himself in images of people that are holy, perhaps a poster from the movie “The Passion”, a crucifix, some pictures or little plastic statues of saints.
Pray when your feeling tempted, believe me it’s a lot easier to avoid MB when you first start feeling the temptation. Either come up with your own prayer or pray some Hail Mary’s when you first start feeling the enemy.
Distract yourself, when you first start felling tempted after you say a short prayer he should try and distract himself by taking a coffee break if he is working, or getting back to work if he is taking a break, maybe he could call you and you could talk about something (I like to play video games to distract myself), whatever it is he has to make his mind change the subject.
Keep busy, this goes hand in hand with the last thing I wrote, but I find that I am tempted more when I am bored and my mind wanders. Have him find a hobby or something he can do to keep himself busy.
That’s pretty much all I can think of for now, but also remember this quote:
“The path ahead of you is never more powerful then the force behind you”
When you’ve got God batting for you, anything is possible.