Most Helpful Girl
That's incredibly crude and disrespectful to be honest. Everyone wants to feel beautiful/worthy so to tell someone they aren't attractive is an obvious tool to cause them some sort of pain or hurt. Seems like he's downright arrogant or plain insecure and wants to put you down.
Most Helpful Guy
It kinda seems like he wants you to believe that no one else will want you, so you have to stay with him no matter how much of an a**hole he might be. Decide for yourself why he would want you to believe that.
You're probably better off without this guy, honestly.