relationships

My boyfriend literally refuses to say I love you on any kind of social media and I just can't understand his reasoning why. I'm not forcing him to say it but it kind of hurts to see all the other relationships saying it and I want to say it so badly but I know he won't say it back so I don't want to be embarrassed. Can someone help me with some advice to why he may refuse to even come remotely close to posting he loves me?