I don't think there is anything wrong with your son. My step-son, who is five years old seems very similar. He likes cute things, like puppies and babies. He will say the same thing, "aw what a cutie, or that baby is cute." He will say the same thing about clothes. He will tell me that we look cute today. I think its because he is very attached to both me and his mother, and is closer to us than his dad. We both say things like that, so he is just saying what he hears all day. He also, acts differently around his dad like your son. I think it is because, like you, me and his mother treat him more like a baby, than his dad. My boyfriend says the same thing as your fiance. But I wouldn't be worried. I think that if you start worrying about it, and making it obvious to him that you think he is acting different or not normal, then it will become a problem. When he starts pretending to be a girl or wanting to wear girl clothes, then I would start worrying. But for now, just let him be himself.