Please help me understand this boy...?!?

[The_heart_hacker]

i think 3 years is more than enough for knowing that he loves you or not. And as you said you told him that you likes him but his behaviour is still same as before and he continue flirting with you, its mean he does not loves you. As he like your all pic on facebook and always gives you compliment its may be or may not be happens in love but in filrting its surely happens. So if someone always admire you that does not only mean that he or she loves you any other reason can also hide behind this.
ultimately i can say that boy does not loves you because in love you cannot always get compliment.
Love is a sweet feelings of affinity.
However, you can check it by your own way.

Good luck.