We bought our house when we were engaged. We actually got married just a week or so after we closed on the house. No problem getting a mortgage, but we did make sure the contract was written with joint survivorship rights (in case one of us died before we got married, the other would inherit the house) and we also made an agreement on what would be done if we didn't get married (since we had been engaged for about two years without setting a date at that point).
I agree, though, that it is a big leap to make if you're unsure about the future of the relationship.
I agree, though, that it is a big leap to make if you're unsure about the future of the relationship.