Any sexual sensation

I have a really hard time feeling anything during sex. I get excited with the anticipation of sex or even making out but while it is happening I get so bored. Masterbation is the same way but better because I can force myself to focus. I have had this problem from the first day I had sex, which was about 5 years ago. I masturbated a lot at 13 and 14 but decresed at 15. I have always been with men I thought about being with a women but the dating idea is not exciting for me that way. I am not A sexual as i really want to have sex, I just simply stop being horny when sex is happening. I am wondering if anyone has or had the same problem. Any advice would be appreciated.