Want to adopt a dog, but my boyfriend is afraid of it. What to do?

I have been searching for a dog for my son and I for a few weeks now. I found a few that I am considering, but the latest one is a beautiful Rottweiler/shar pei mix. She is about 2 years old and from what her foster mom tells me, she is patient, submissive, a so gentle with young children. So much so that my 5 year old could walk her on a leash without her pulling. The problem is, my boyfriend (who does not live with me, but I care about tremendously), is terrified or Rottweilers. If I choose to adopt this girl, what can I do to help him help him overcome his fear of her? She is said not to have an agressive bone in her body and I can't make him understand that not all Rottweilers are like the one he had a run-in with as a child. Advice? =\