Lately I have stopped being fully Shomer Shabbos, spending Shabbos afternoons in the bedroom surfing the internet on my phone and texting non-Jewish friends. My wife and children think I'm sleeping this whole time, and they knock on the door to "wake me up" and have me come down to make Havdala. Is there any point in my making Havdala? Would it better to have one of the older (above bar mitzva) boys make havdala if I haven't kept Shabbos? It would not be totally odd since we let them make havdala sometimes.
What about Kiddush if I am not really sure whether I'm going to break Shabbos?
I know what I do on Shabbos is my own issue and not for this forum, but I'm worried about messing up my family's observance too, so I don't want them to know, hence I'd prefer to make Havdala for them as usual, if it makes sense.