Relationship expert Matthew Hussey is back with more relationship advice, this time about long-distance relationships and the response that should be the ultimate red flag. Matthew Hussey is a British relationship expert who has appeared in publications ranging from Cosmopolitan to GQ. Boasting 1.7 million followers on Instagram, Matthew often offers stellar advice to his followers like his top tips for bagging a second date. What to watch out for in a long-distance relationshipDespite only lasting five months on average, most adults have some experience with long-distance relationships. The d…