But the example you gave of a gay character as "mentioning sex" wasn't any more of a mention of sex than what you are doing every time you refer to your "brother-in-law" or "kids".
Happens all the time. Someone mentions a husband, they're a dude, someone else says "hey, let's not talk about sexual orientations here".
I know you said it. I believe that you are also sincere. However, that is not how human brains work. Humans notice unusual things but not commonplace things. I've been watching people do this for years. If they believe me to be male, and I refer to a "wife", they don't notice that I said anything that might imply something about orientation, but if I say "husband", they notice.
No. I don't need excuses if I want to be a jerk! However, I don't believe this thing because I've never seen it be actually true, and I've often seen people say it, and clearly sincerely believe it, but at the same time their actions prove that it's not true.
Except that, in reality, if I mention a same-sex partner, people say I shouldn't talk about that near kids, while if I say the exact same things about an opposite-sex partner, they don't notice. When I mention the same-sex partner, they think "I just heard something about sexuality".
As noted, "protecting" the innocence of kids is a disasterously bad strategy. Kids are really good at discarding information they don't care about, and generally if they can ask the question, they can handle the answer.
No one suggested that you ought to. But what usually happens is that people will let someone say their character is married, but if the partner is same-sex, they suddenly declare that this is Exposing Kids To Sexuality.
Maybe you really don't do that, but the fact is, the level of mentioning of relationships you did when describing your table is something that I have frequently seen people react to with hostility and assertions that it is "shoving your sexuality in other people's faces".