2 dogs?

I'd really love to adopt this baby http://search.petfinder.com/petnote/displaypet.cgi?petid=6533752, but I'm concerened about taking on a 2nd dog. Harmony is very dominating and an attention hog. Currently I live with my parents and their 2 dogs, but soon they'll be moving, so it'll just me my fiance and our Harmony. The 3 dogs don't fight, but Harmony gets extremely jealous if we try to pay attention to the other dogs, and won't let us play with them. Also, I'm not sure how difficult it will be to train Houdini, who's deaf. I'll be starting my student teaching in the fall, so I'll be very busy and my fiance travels a lot for his job. But he's such a cutie and I love the idea of adopting another piggie in need. Anyone have experience this this? Any advise on either thing?