How can I end this

[Makemedoit]

I have been seeing some one for a few weeks but for me it has gone as far as it can go. He seems to really like me but I really don't feel the same and he is beginning to irritate me.
Can anyone help with some words to make it as painless as possible for him?

A few weeks??
'Hi X. I've really enjoyed the time we spent together but I don't see it having a long term future. I wish you all the best! Make'

What Codename said. Just tell him you've enjoyed yourself, but you dont feel there is any future in the relationship. Wish him well, say goodbye. Easy.