I have just read a post dated 12th August in ‘My Journal’ the thread ‘Day Two is Still a Day Away’, written by Paul 315 where he talks about ‘shouting’ a strong yes because he read in question 19 or the Gamblers anonymous 20 questions ‘did you ever have an urge to gamble to celebrate good fortune by a few hours of gambling’.   He had made his decision to live gamble free and he was so enthused by it he gambled.   It happens.  
Complacency is the greatest danger to the CG in recovery.   Accepting that they will always be CGs but that they must control this addiction for life is tough.   Personally I think it is tougher than any decision most non-CGs will ever take and we cannot know how we would cope.  Your husband has tested his addiction because he stopped believing he was a CG but slips do not have to be negative, working through a slip can make a CG stronger for the future
Your husband should put his disappointment behind him.   For 32 days he has enjoyed the freedom of being gamble-free even if they were not the easiest days.   He has let himself down and I am pleased he knows it but a clean date is there for him.   I wish him well.