Welcome to the boards!
let me start off this reply by saying that there is nothing wrong with you. by saying that he doesn't get turned on, are you saying that he doesn't get an erection? if this is the case, there could be a number of answers (the last of which would be him not wanting you).
for example, is he a virgin? if he is, then lack of an erection could be considered somewhat normal. many men get what is loosely referred to as "performance anxiety", in which the pressures of sex may be overwhelming to him and he may be afraid that he won't please you or live up to your expectations.
the best advice I can give you is to talk with him about it. couples should be able to share things like this with eachother without feeling embarassed or insecure.
finally, the last thing he needs if there is a problem with anxiety is more pressure. he may already putting enough pressure on himself.
hope I was helpful
