What should I do about sexless marriage

my husband and I married 6 years ago. We were sexually active when we first met, but then right before we got married, I noticed we weren't having sex as often. I questioned why he had so many playboy magazines in his home, but said it was told it was "good reading material". I also noticed several tubes of ky jelly in his home, after snooping when I became suspicious there might be someone else. We haven't had sex in 5 years and feel so lonely. I have discussed my feelings, but am told that he is too tired or just not right timing? I am losing my patience.