Why does my boyfriend like to make love in the same position?

I have lived with this man, who is 10 years older than me for almost 8 years. I've tried asking him, and he gets very offended. The few times we do make love, it is so predictable, that I know exactly how it will happen. He wants me to give him a back massage, then foot massage, then he wants me to go down on him for a few minutes, then he wants to get on top of me for about 30 seconds, then NEVER finishes. He used to be such a good lover when we first met, but now the experience is more than lame. I am hurt too, that he has gotten so selfish. I love him very much, though, and don't know what to do. Just wanted to know if there are any other women out there that have had the same thing happen to them? He NEVER wants to massage me, and I feel that he is not really turned on by me any more. Let me point out that he takes a lot of medication for diabetes, high blood pressure, and Xanax for anxiety. I feel lonely, rejected, and sad, plus horny as he**! He even threw out the vibrator we used to own. Of course, the only time he used it on me was when we were drunk, after a night of partying! Now, the few times I do get laid, it is like this. I am a very sexual 37year old woman, who would love to experiment, and be a little kinky sometimes, but....no can do with the man I love. He won't play with my big DDD boobs, touch me downstairs, or even kiss me anymore. No doggie style, nothing but missionary position.