Am I doing something wrong?

I've been dating my boyfriend now for about 8 months and I find that he just doesnt want to have sex with me. I've tried dressing sexy ,making us change our diets for more libido(which supposedly has worked but still nothing), ive iniated quite a few times and even tried not iniating it but somehow doesnt work. I've asked him if he is even still attracted to me and claims he is claims he is serious about our relationship. He claims he see's marriage in our future but I just really wish we had a sex life I feel a constant sense of rejection from him. The sex we do have lately frankly hasnt been all that great just not enough foreplay gets really boring really fast. I'm not ugly I could find another guy to **** in a heart beat I just wish the one I wanted, wanted me back. Am I doing something wrong? i've communicated this all with him and I just feel it doesn't make a difference. I just miss the attention sex brings makes me lonely.