Why i lose interest :(

I have this addiction since 13 year old i am 18 now i have a girlfriend we have been together for 1 year now but the 3 first month or 5 month i was in love etc after i start doubt my love for her Even my family i feel no emotional connection with them i am cold etc but sometime i feel it i feel love like sometime i have this moment like omg i am so lucky of having a girlfriend like this etc but when i fap a lot i lose interest and my emotional connection to :(