Helping my husband

When my husband and I first got together we fucked like rabbits and we could go for hours!! For awhile now though he goes really fast and once he goes he wants to just go to bed even though most the time I'm unsatisfied. If he doesn't go he stays rock hard but if he doesn't go after 10 minutes he gives up and goes to bed. Is it me or him? How can I get our spark back so we can go for hours again? I want to be satisfied with making love to my husband.