There's only City for me.
I have a number of teams whose results I look out for and hope they win - West Ham, Rangers, Hibernian, AC Milan, Sampdoria, 1.FC Koln, Eintracht Frankfurt....
The nearest I come to "supporting" another club is Hull City but it isn't a patch on what I feel for Manchester City. I've lived in Hull for 20-odd years and because of that, often get offered mates' season tickets when they don't go for whatever reason. My Godsons are Hull City fans and I went with them and their Dad, my best mate up here, to their first ever match.
I dearly want them to win for the people around me and also so I can get a taxi home from an away match when they're in the Premier League but there's nothing in my blood for them.
Earlier this season, one of the Godsons asked me at a match why I wasn't angry at the referee who was having a piss poor match, I thought "because it only really bothers me when it's my Citeh" but replied to him - "I want you to win but it's not my team, like your Dad when he watches Manchester City with me."