Hi, I hope someone can help. We have two Cavaliers, George (tri, 3 years old) and Millie (Ruby, 2 years old). We have just brought home our English Mastiff puppy, Spencer, to add to the clan. We are not expecting this to be an easy process (somewhat different to bringing up Cavaliers), we are trying to anticipate all problems, a dog trainer is visiting this week, then he is attending dog training as we want a well socialised, well trained dog. However the problem we have first is with Millie, she's really scared of him. George is quite happy, a quick growl keeps Spencer in his place and they have started playing. Millie (who is the sweetest natured dog ever, I've never heard her even growl at anything), runs away from the puppy, tale between her legs. She is still coming down to eat, but is basically just hiding upstairs. How can I help her, I've read we shouldn't try to reassure her too much around Spencer as that confirms to her that he is a threat, but I don't want to ignore the problem. When she was a puppy a black Lab tried to attack her (no physical damage done), since then she has been exceptionally submissive to other dogs, but not terrified. She was brought up with George and an Old English Sheepdog/Irish Wolfhound who we sadly lost last year. She was happy with both. Sorry for such a long post, but I really want to help her, not accidentally make her worse. My heart breaks for her, she really is the nicest, sweetest little girl. Thanks in advance for any advice.