My son is taking out a mortgage in his name only. His girlfriend is moving in soon. At some point in the next three years or so they’ll want to move to a bigger house. His mortgage will be portable. What happens if they want to include his girlfriend’s income for the new property and take a joint mortgage? Is this still allowed to be portable or is it considered a new mortgage? We are trying to decide whether he should have three year fixed or ten year fixed. Don’t want him to have to pay exit fees if he gets a joint mortgage in a few years. Any ideas?