When we got Franklin, it was love at first sight. We went to the breeder's telling ourselves not to get attached and that we needed to look at other dogs. My boyfriend was the rational one, telling me all this. The minute we saw Franklin, he said "get out your wallet". No joke.
With Maggie, it was the opposite. She is a "rescue" of sorts. We adopted her from a breeder who just didn't have the time to take care of her anymore. When we brought her home, I was almost in tears I was so upset. We had a stressful day and she was scared and confused so she kept snapping at and trying to attack Franklin. Not only was there not an instant connection but I HATED her. I feel guilty for admitting it but it was true. I had envisioned a perfect little family with my boy and girl and here I had this dog that was attacking my dog and being a total pain.
Turns out, it was just the stress of the trip. After a couple of weeks she opened up and today we couldn't love her more. Don't tell Franklin but sometimes I love her more.

She is the sweetest, most loving dog I have ever seen. She is behaved, responds well to my commands, and basically is the perfect dog. We LOVE her and we really do have that perfect little family I wanted.
So, it's normal for you to not feel that initial spark. It doesn't always happen right away. I'm sure that he's just nervous and anxious and scared. He will open up to you soon and steal your heart before you know it. Good luck!