You came on here looking for advice and so i suppose that it is not fair to make overly personal remarks, so here is some advice and my charge is that I get to make a modified personal comment.
Advice first, you are in a strong position particularly if your partners teaching job is permanent. You will be giving the bank valuable business, be choosy about what mortgage offer you accept. Remember the bank needs you at least as much as you need them, if they cannot lend to people in your situation who can they lend to.
Personal comment next. You are adults looking in getting involved in a commercial transaction, but you have the attitude of school children looking for a favour from a strict teacher. About your debt you say " but (we) never missed a payment". Well aren't you the good boy and girl.