What do I do about leaving my partner of 10 years to live in the UK permanently? We have a dog together too :(?

I have already moved to London for my graduate degree (MA) and its been several years since we lived together. We have tried to make it work, but he has absolutely no ambition and is not happy with his own life. I feel like he is relying on me to 'make' our life together and 'make' him happy. I know its over between us, but we also have a dog together. She is the absolute animal love of my life, and I would be extremely distraught if I could never see her again. I don't know if I can get a permanent visa here yet (working on the extended one now) but I don't see myself having the extra time to run home on the tube and walk her. He's not vindictive, so I don't think he would keep her from me, but I am afraid I am also missing huge parts of her life and somehow shirking the responsibility I have to her by being here. He says he can't 'go off and chase his dreams' like I have, because he has to be home to take care of the dogs...but he doesnt have any dreams! I asked him the other day on Skype where he wanted to be in 10 years, and he has no idea :/ Its not like we're kids (I'm 30 and he's 29 tomorrow)...and its been a long and very hard road for me to get where I am now and as happy as I am. I know these may sound stupid, but I have no parents to talk to and no close friends here in London...Help!!