Relationship advice anyone? Please?

So basically, I'm in a "relationship" with a guy that i saw in a pub and then i tracked him down through facebook (stalking i know) and we've ended up together - i've been with him just over a month and i don't really fancy him as much as i thought even though i can't pinpoint what's missing - but since i tracked him down i feel like i can't tell him i don't want a relationship with him - plus he used to self harm because he felt crap about himself so i don't want him to feel like that again either. Soooo after that long-winded explaination does anyone have any advice?