It's a shame that you couldn't just be honest with this person when you first met him by explaining to him that you don't have very high self-esteem in the first place. Yes of course you should come clean with him and hope for the best, but you also have to understand that if you want to be in a meaningful relationship with somebody then you've got to be honest with them about the way that you feel about things, otherwise you'll just be a wolf in sheep's clothing. If I were you I'd be scared and reluctant to come clean with him too because there is a chance he may not be so understanding. If he isn't, then I empathize with you in losing someone you love, but at the same time I don't think you'd really want to be with somebody who doesn't fully understand the depths of your character. I'd hope that your standards are higher than that.

I agree with the first few posts that advised you to be honest and come clean with this person, but I think its most important for you to come clean with him for your sake and not his. By keeping the lie alive you're simply denying the fact that you have (what seems to be) serious self-esteem issues, thereby running from them when what you should be doing is confronting them head-on. It's scary sometimes to talk about issues like this with people, but I think you'd be really surprised at how common low self-esteem really is. A lot of people have experienced it or are experiencing it right now, and if there's anything that can take the edge off of rough times it definitely includes not having to experience those rough times alone.