The only thing im thinking now is that back at the beggining he said out loud "i love you" at the street thinking about Rikka and a girl from his school heard it and later notice him at school. Maybe wont end with only 4.
But his rather stupid. Its obvious they will found out eventually so at the very least he should come clean before things get worst. But forget about love my boy, not only u've been negleting Rikka but also 4-timing her.
Wonder if this will end with him dying and lifting the curse from the others.