Yes as others have said OP, it isn't necessarily the best time to buy right now if there's even a chance you might have to resell in say five years or less.
So financially, if I were you I'd rent for a year - because if the worst happened - house prices dropped, and you bought then split up in say three years, you could lose a hell of a lot more than the cost of a year's rent, on top of the hell of actually getting the VALUE of that deposit back (i.e. getting it all back at once, rather than some proportion of it paid in dribs and drabs - you get the idea).
Similarly, if you rent and house prices fall by this time next year, you could be quids in through having rented for a year.
We were thinking of buying in the place we currently live - wanted out of our current rental, thinking (like you) why pay rent when theoretically we could buy.
However. We have a good idea that we'll move cities in three years or less. So when we did the sums, it didn't really add up. If prices dropped and we had to sell (moving for job) we could lose out quite badly. Far more than by renting!
At the moment, it makes a lot of sense to not buy, even leaving aside the relationship issues.
Also - once you have bought together, as HardCheese says, there's a subtle pressure to stay together. You've committed, it'll be hell on earth to split it all up and you'l both lose money, so let's muddle through... that isn't a great situation to be in, frankly.
I say again - just rent for a bit! This is one of the biggest decisions you'll ever make. It's worth not rushing. It's worth losing some money renting, too. Well worth it not to lock yourself in with the wrong guy. Well worth it to give yourself the peace of mind that you know he's the right guy. As much as you ever can!
And if he's the keeper you hope he is - he'll understand this, and should go for it too.