You didn't say how old you both are, but your dilemma sounds like a situation that could happen in adolescence. If that's the case, your friend could be too immature, shy, inhibited and/or embarrassed after the kissing incident to have the kind of boyfriend-girlfriend relationship you are hoping for.
If, however, you're both a little older, say in your twenties, then you might want to consider that, for most guys, being friends with the rest of your family would not stop them from pursuing a romantic relationship with you if they really wanted to. And that may be the real question: Does he really want to?
It may be that, like the movie and book title, "He's Just Not That Into You." If a guy is interested in you, then he will usually find a way to communicate that to you unless he doesn't have a clue about dating relationships. In the latter case he may need some initial help getting things going. This is the strategy behind having your girlfriends help you out by hinting that you like him, or asking him to be somewhere and you just happen to show up at the same time. These are age-old tactics that can sometimes wake a guy up to your interest in him. They could help if you think it's a case where all he needs is a little nudge in your direction.
But since you've already kissed, it doesn't seem too far out in left field for you to have a conversation with him about what happened between you. In our society, with its double standards for men and women, it is more difficult for women to be direct with men so, on one hand, being direct carries the risk of scaring him away. On the other hand, he is already away, so there's not much to lose (unless you are concerned about saving face). If you have the conversation, it would end the guessing games so long as your friend was willing to be truthful.
All of the above notwithstanding, when you say, "We like each other but he chooses not to continue with a relationship," it sounds like you already know the answer. A more appropriate question for you to answer might be whether you want to be with a guy who's ambivalent, hesitant, or resistant about wanting you to be his girlfriend. Don't you deserve better?