You could do what I do..... Whine and complain about it for a while and if he continues to say no get it anyway! LOL
That's pretty much how I ended up with BOTH of mine. Hubby isn't much of a dog person, but he didn't have too much to say when I brought 'em home!
But then again... He can be a pushover when it comes to stuff I want and I'm 100% responsible for their care and any costs involved with it....
What do you think your husband would do if he came home one day and there's all of a sudden another pup??!