Dog Visitation Rights?

I broke up with my boyfriend over 2 months ago and had to leave my dog because I moved to MN for school and I couldnt take her with me. and seeing my dog was never a problem. He recently started dating someone new, and all of a sudden said that I was not allowed to see my dog ever again. She is like my child. I love her more then anything else. When I first went and saw her after 3 weeks of being away, she knew who I was immediatly and went crazy, and literally started crying and was howeling saying mama. No joke. Even when he puts me on speaker phone and I start saying her name and that I love her she runs around howling and barking and looking for my voice. I picked her out with my ex when she was only 4 months old. We were never married, so my question is, do I have visitation rights? I cant go back to Iowa very often, and All I want is to be able to see her when I do. I can only go there about once a month, but he is being such a jerk about it. He says that if I take my name off the energy bill, he will change his number and never allow me rights to Chloe. So Im stuck in not only an emotional situation but a financial one as well. When Im away from Chloe I feel like Im missing a part of my soul. Help!