Why does my husband masterbate, leaving no penis energy for us ?

My husband get high on meth and masterbates so much. He notbonly jacks off, but he ass fucks himself with huge homeade cocks he puts condoms on over. Ive found them when i snoopee thru his bathrm. Worst part, it ruins his hardon and he goes limp when we finally try to fuck. Makes me really angry. I mean, i will masterbate thinking about him whacking off, not all the time bit when that urge is there its great. But he never knows cause hes always on the other side of the door. HELP