First Dance Songs

I also agree with Tori. My sister and BIL did Small town girl by Journey and it was amazing and different.

Finding different versions of the song that are more instrumental or slowed down would work too

I'm not familiar with the song, but I agree with Tori; first dance doesn't have to be a slow dance. You could choreograph your own moves to dance to. Check Youtube and see if another couple has done Longer as a dance.

If your fiance is set on having a slow song, you could maybe use Longer elsewhere--like during the signing of the register, the recessional, your entrance to the reception, or your exit song at the end of the night.

I think that the speed of the song is too fast for a slow dance but your first dance doesn't have to be a slow dance. If both you and your FH agree to not doing a slow dance then it would be a fine but if he is set on the slow sway back and forth then perhaps you could find find a slower version or get somebody to sing it at a slower tempo?