Yes, I'm glad people have raised the issue of the potential temporality of the Australia thing. In this academic climate that we're in, it's not a foregone conclusion that a post somewhere will lead to a permanent situation in a particular area. May I ask what discipline your ex is studying in? If it's science, then different considerations will be needed; but if it's arts, then please do think about the haphazardness of putting all your eggs in this basket. I myself have the possibility of doing postgrad study in NZ, and it's not something to be taken lightly, especially if there are ties keeping you in the UK.
Like others have said, is it possible for you to postpone your studies for a year and follow your ex out to Australia, if it's only for an MA, then for 12 months or so? Universities at BA/BSc level can be so accommodating, and I'm sure will fully understand your situation. What subject are you yourself studying? Unless it's Medicine or Law or Veterinary Science or Engineering, I can't imagine it's going to be something which absolutely requires three years on the trot.
As for the adoption/abortion thing, it's really your call. I can only speak from my own perspective (as can us all). I'm not sure in 1989 whether abortions were possible in the Soviet Bloc of eastern European countries, but if they were, then at significant risk to the woman's life. In any case, she chose to have her baby, and give it up for adoption. Who am I to say that I'm glad for being alive? My life wasn't in my hands then, and, though I can speak as a 'believer' now, I trust that God would have redeemed the situation, even if my mother had terminated her pregnancy. Of course it's not ideal -- neither is adoption. But this is real life. I'm only sorry you have to go through such a difficult decision at so young an age. I think it's so important not to internalise any sense of guilt or idea that you are a failed woman because of it.
But really, my deepest sympathy lies with you in the sense that you say you still love your ex, and I can totally understand that you see your baby as a part of him, because, quite frankly, it is. No one should call you foolish for wanting to have the baby even for those reasons. So I think the onus is as much on your ex for considering what he values in life and wants; I only hope you both don't let bitter resentment to eventually eat away at any fond feelings you have had for each other.
Hold tight, and my thoughts and prayers are with you.