[yorkietalkjilly]

Not being there or getting to actually see the two of them or get a real-time, in person sense of the situation, see his/her body language, it's hard to tell for sure but from past experience, I'll tell you what I've experienced when a dog behaved like Wallee is being described. I think he's trying to discipline and show her he's in charge, not teach her how he's been taught to behave. Why would he even want to do that if he's not thrilled to have her there yet and is totally happy with her? To him, I think he's still viewing her as an interloper and thinks she's no right to greet you first or happily. It's just part of his natural doggie jealousy or leadership role and sees her behavior as that of horning in on his territory and people, perhaps trying to usurp his position. He likely still sees Summer as a challenge to his authority or place in the pack/family whereas the didn't view the other dog he treated differently as a challenge at all. A friendly, submissive dog is usually accepted by most other dogs as they are willing to take any role offered them in the pack but one that vies for an equal or higher role is viewed differently by the long-time pet whose territory is being "invaded". They've more to work out and settle between them. It can take a full 2 months to make progress with most dogs.

I believe I would give them both a break in the next few days - take her away from the house for a few hours for a grooming session, even just a half-days boarding at a pet hotel or a long outing in the park and allow him some alone, free time to deal with being alone and without her company and see how he greets her when she returns. If he's glad to see her and runs to greet her happily, he's coming to accept her as a family member, albeit one he feels he's got the right to dominate as pack leader. If not, he's going to need more time. In a few more days, I'd let him be the one to spend a half-day or so away from the stressful situation and see how they interact upon his return.

If, in another two weeks or so he's still chasing her and disciplining her reactions when you arrive home or bring out toys or anything that elicits her excitement and attempts at showing joy, playfulness, I'd stop it and tell him "No", point at him, lock eyes with him and walk into his space, backing him off and staying there until he leave the room. By then, it's time to start teaching him that his discipline of her is no longer acceptable.