Hi sweet13, I think it sounds like there are two issues here, one being your boyfriends self-worth and two being your own feelings as to whether you want children or not. I don't see this as a reason for throwing a relationship away right now, although I do have a friend who at 28, has been married to a man for 3 years, who is now 40, who categorically does not want children, and it is a nasty situation to be in. They love eachother but will have to go their seperate ways or end up resenting eachother I guess.
Personally, I would suggest that maybe you attend Relate relationship counselling together? I cannot rate them highly enough; myself and my fella had a few issues in the early days and now, five years on (married, with mortgage and got baby on the way!), I can safely say that we would not be together now and it would have been over daft issues that were so easily sorted. I am sure it will help to make you both see things a bit more clearly, and if you decide that going your seperate ways is what you have to do then you can tackle that when you come to it.
Good luck hun, I hope it works out for you xx