How do i get him to want me again?

I feel as if hes interested in other girls and dont get me wrong like were in love and stuff, but like things have changed i feel as if he is not interested in me anymore, is there something i can do so he realises that he misses and wants me. Another thing we both have this girl mate and i am not that close 2 i will say hes more close 2 her but like i dont get whats going on if i text her she never replies but if he texts her she replies within that minute and it really ticks me of but he dont see that. I feel as if im loosing him.. (We been together for 2years nearly but things are just getting boring or im either getting blanked coz hes always busy) Thanks for the help!! xx