AITA for wanting a second dog?

My boyfriend of 5 years and I have owned our own home just over a year. MY elderly Great Dane became OURS the second we got together but he was still my baby. When we found out our pup wasn’t going to be around for long due to health problems (around May) I petitioned for a puppy. I have some mental wellness issues and need that unconditional love dogs provide. My BF (though he loves dogs too) said he wanted to try to live dogless for a while, which I vetoed outright. We compromised on a 3 year old mastiff bulldog, who we adopted in September after losing our Dane in August. I did all the work, searching petfinder and local shelters and rescues, filling out the crazy applications and coordinating with the necessary people. Essentially, the issue is that our new guy has bonded more with my BF, which my BF fully acknowledges. Don’t get me wrong, I LOVE THIS DOG. He’s smart and funny and everything we were looking for but I don’t feel the same attachment from him that I had with my Dane and want to get another dog, specifically a younger dog. My argument is that two dogs is really not that much more work (which we totally split fairly) than one and I’m upset I don’t have the connection I was looking for. My BF says I’m an asshole for getting what I wanted and not being satisfied with it. We’re not gonna break up over this or anything but it seems one of us is gonna be a bit resentful either way. Thoughts?