When Riddle first saw you, he was both shocked and disgusted since you were big in terms of both weight and height, especially because his mother used to under feed him and would tell him that people of weight were just unhealthy and unhappy (this bitch).
But after he started spending more time with you, he realized how great you actually were and slowly started developing a crush on you. This of course didn’t go unnoticed by the rest of the Heartslabyul boys (It took Deuce more time to realize it than the others but he connected the dots at some point) and they would tease Riddle about it but he always denied it.
Riddle enjoyed the time he spent with you even when he would remember his mother and think of how she would react if she found out about his crush on you (personally I would kill her before she would open her mouth-) he’s just glad that he could spend time with you away from her and her rules.