if his pay gets transferred into the bank account every month,
the easiest is to set up a standing order, such tt on a certain day
of each month, a fixed amt of money will be transferred to another
account (which he cannot touch presumably).
right now i do the transferring manually every month.
this way the amount of money he has direct access to will be
lesser.
another tremendously useful (but slightly more tedious) way is to
get him to record down every expenditure he makes each day. we tend
to spend very willingly when we dunno how much we haf spent. by
recording very visibly, it becomes very clear how much we spend
daily on wat items. this tends to make one less inclined to spend.
useful for keeping track of monthly spending too, esp when one
likes to use cards alot - very invisible, very dangerous!
at least it has worked for me. 
