How do I show how I feel?

[MikeIsNotPG]

My boyfriend has brought it to my attention that I don't show him how I feel and he's right. Emotionally I treat him like he's my own personal fuck toy, and that's awful. So I want to change this about myself but I don't know how. I'm not saying I have no emotion, I'm saying that showing that emotion is difficult for me. So much so that I genuinely don't know how. So if someone could give me some tips aside from the obvious "Just tell him how you feel" unhelpful bullshit. I don't know if this is some sort of mental condition or if I'm just a colossal twat. Either way I need help.