lilly40, I guess the transition from having a fun relationship to becoming a committed father was just too much for him? I know that you get to a certain age when you feel that you have put your parenting years behind you and are now looking foward to some freedom, extra cash and a bit of fun.
Of course you probably feel the same way and unlike him, you can't just walk away from this, you have to face it and deal with it.
I would perhaps write him a letter. Tell him that you understand what a shock it must be and that it's equally a hard shock for you too. The thought of going through all those years again can be immensely depressing. But tell him that this is not a problem that you can walk away from. He may be able to bury his head in the sand, but you both knew that having sex may lead to a pregnancy and now you have to do the adult thing and talk about it.
Tell him that for you, personally, an abortion is not something you can go through with, although this doesn't mean that you are happy about the pregnancy at all, it's just a decision that you cannot make and you hope he can respect this.
Say you want to discuss this with him, that you miss the fun and laughs you both used to share and that whilst you understand if he doesn't want the commitment of another baby, you do deserve some respect from him at least. This is not an accident that only affects one of you, this is something that will affect both of you so you both need to talk about it as hiding will not make the problem go away - and you have to shoulder this far more than him.
Give him that chance to get in touch. If he doesn't respond or doesn't want anything more to do with you then I'm afraid you really will have to reassess your options. At least you know now, if he's the kind of man who refuses to face up to problems and refuses to shoulder responsibility, rather than further down the line when you fall in love with him.
If you really don't think you can manage on your own with a baby but don't want an abortion then you can always consider adoption. It's just another option that is out there. But if you do decide to keep the baby, you never know how things might turn out but it could be the best decision you ever made. Life has a funny way of doing that to us sometimes.
I hope he comes round x