The best way to build a relationship with any dog is to do things with them. Take them for walks, do training, play with them, and take them places. Of course we want to move at a speed the dog is comfortable with but if we simply do things with them the dog will start to trust us and want to be with us more.
We get dogs in here all the time who may have aversions to strangers. Yet all those dogs leave in a better space not just training wise but they actually enjoy our company. Why is this? Because we spend a lot of time doing things with them. Training sessions, walks, just hanging out in the same space. On top of that I think a major component is that we do not spend a lot of time petting them. Sure, they get pets from us but we are not over effusive about it. A good spat of petting for recalling off something hard is a lot different than just snuggling on the couch or in bed. Snuggling does not constitute doing things. Sure, they may like it but your not any closer to having them truly have a relationship with you. I know this because a lot of the dogs we get in come from homes where there is lots of petting and snuggles yet the dog doesn’t listen or bolts at the first chance they get. They remain super disconnected and tuned out.
So, back to the question at hand. How do you create a relationship with a new dog, old dog, spouses dog. Take them out and do some training.