When did you know you were in love?

The infamous question...When did you know you were in love and not just loved your partner? I’ve been with my boyfriend for 3 years and I honestly I love him dearly. I’m grateful to have him as a friend and lover. I know I’ve been head over heels in love in my first relationship ever. With him it’s different and sometimes I question if I’m truly in love? I’ve never asked him before because I’m afraid of the answer even if he says yes or no. 3 years is a long time to not completely be sure and this scares me. Wouldn’t I know by now if he’s the one? I go back and forth with this. We’re moving in together really soon and I hope during this time our love continues to grows and I know for sure that I’m in love. Have any of you all been in a similar situation or had similar thoughts?