The difference in I love you and love you

I’ve been with my boyfriend for about four months now. Things have been rocky lately and I’ve noticed his “ I love you” have turned into “ love you.” I asked him why and he said it’s just what he says to his family he didn’t think that much into it. But I told him to me there’s a difference so he started putting the I again.

Am I overthinking or is it obvious emotions have changed?