I was in a similar situation, with another amazing man, and as much as I loved (and still do love!) him, there wasn't any *spark*.
Granted, a lot of long-term, very healthy, happy marriages don't have sparks, or fireworks or whatever you want to call them...
My thoughts are that if you started seeing someone so soon after your makeout session, this one probably isn't what you're looking for long term- or he *is* "if only ____"- it's the blank you need to fill in
Best of luck, and I wish the best for you (& Nick!)