I'm not sure what you mean by "small" but I am assuming that perhaps your breasts or your vagina is small? I really doubt that your size has anything to do with his apparent attraction or disattraction to you. Not all guys are super cuddly in bed - some are more of wham bamm thank you ma'am and others are git in get off get out.

It is a rareity of a guy naturally being all cuddly during sex and focusing on the foreplay. But before I'd tell him he's colder than ice, try this next time your together. Mention that you get really turned on when he kisses your neck (or something like that he does) Guys LOVE to please - maybe he's just as concerned about YOU not being attracted to HIM! Unless he's a real dog, your sex life will really improve when YOU start enjoying and letting him know you are.