The author's own situation is clouding his judgement. It is entirely easy to predict that asking if you have kids is going to lead to asking about a wife. This is the way family life has gone on for centuries. It's only recently (in generational terms) that gay couples could adopt children or even be openly gay and married... yet the author thinks that there's no way to predict how someone is going to steer a conversation. I wouldn't take offense if someone steered a conversation in the wrong way because it's more about their reaction to the surprise news ("oh, i have a husband not a wife") than to how the conversation found itself. Maybe I perhaps steered the conversation the wrong way instead of the cab driver.

As an aside: I had to rewrite this many times because I didn't want to come off as being homophobic, discriminatory, or what have you. I really don't like walking on egg shells, but some topics really cause other people to pounce.