The problem here is not Newcastle but that the 'partner has decided' - was there no discussion? If you say no, will he leave you and go anyway? If you go and hate it will you be miserable and blame him, and split up, and what then? Would it have to be in Newcastle or just outside? Tyneside/Whitley Bay is on the coast but the Metro takes you into town.
Having sorted that out, I have to say that, as a regular visitor, Newcastle has a lot to offer. Wonderful deserted sandy beaches (albeit a bit cold and windy), art, culture, super friendly people, your ear will attune to the lingo after a year or so.
But if you have a lot of friends and relatives close to where you are and don't want go leave them, then you have to choose - who do you want to spend the rest of your life with?
I totally agree that you should spend a week or so there before deciding - it may be nothing like your partner is dreaming it is. Plus it depends on how much you would have to spend on a house as to which area you would be able to live in.