When you are dating, the green glasses may be firmly attached and you don't even know it. Your family usually has your best interests in mind. You may not understand their reasoning right now, but sit down with them and find out what they don't like about him. Step back and try to understand their point of view objectively. You may find out your family truely loves and care for you. More often than not, you should take their advice.
Hannah_Marieee