Frustrated Wife

I have been with my husband for 8 years and married five of those eight. I met him when I was 18 and immediately fell in love after two years we married. Sex was great the first three years and then he started having really bad headaches, we went to the doctor and he was told that he had high blood pressure and given medication, since then sex has been very minimal. I love him so much and have tried explaining how I feel but things are not getting better. When he started the medication we went from having sex 4-5 times a week to only once a week as time has passed now it is only once every couple months. I do not think he's cheating, but I fear soon I will. I masturbate but there is nothing like being touched by a man. I try to stimulate him, I set romantic dinners, I perform oral sex in the middle of the night/early morning and nothing seems to be working. I do not want to seem selfish because I do understand that it's not him and when I married him part of my vows were sickness and health and I still stand by that. I have asked him if he could perform oral sex on me at least once a week but he will not. I am very horny and haven't had sex since Valentines day. What should I do? I love my husband and do not want to cheat but something needs to change. Advise please.