Is it normal that my fiance&i barely have sex?

My fiance and I have been friends for 13 years. We've had a crush on each other for a very long time; when we were teenagers we almost had sex a couple of times.
Currently, we've been together for a year and a half (and living together for 1 year). The sex is ALWAYS magical for both of us. Unfortunately, we have sex once or twice a month. Three times if I get lucky. Once we even didn't have sex for 2 months in a row.
We are both very sexually active people. We are both very much in love. We both find each other sexy as hell. When he is searching for porn online, for instance, he searches for a woman who looks like me: he googles "red head, heavily tattooed, big boobs". And that is exactly me.
We both do drugs (not hardcore though, but we do) and we are both on a medication that kind of reduces one's sexual apetite. However, we've talked about it many times, that our sex life is very unhealthy and that we barely have sex and everytime we have this conversation, we decide to work on it and make it a point that we should have sex at least twice a week. We never end up committing to our decision.
Even when I think about it alone and decide that I will make a move at night, when the time comes I keep postponing until I fall asleep.
Please comment and give me your opinion, but let me clear some points out:
No, we haven't lost our "spark" or "chemistry"; it's still there.
Yes, I do think he is hot and he thinks I am very hot too.
No, we aren't too old. I am almost 30 and he is 32 years old.
Help.