Problems with my boyfriend?

Okay, so my bf is really affectionate, like, he's always saying ily or how pretty i look and holding my hand and stuff. I, on the other hand, am really shy ( HA major understatement) so i don't really say things like 'that' that much ( i think it's becouse i'm a 'pushover' so my bf's usually treat me like dirt and i'm not used to hearing that stuff). It's not that i don't Feel this way towards him ( and i do <3 trust me) or that i don't like hearing him say that but i just feel uncomfortable telling him things like that for some reason, basically im wondering what i can do to let him know that he's my mr. amazing.