I see that this is an old thread that was reanimated recently, but I'll just chime in for a moment.
First of all, I don't know if I qualify as being "a single parent" or not. I mean, I am "single" (divorced), and I am a "parent" (of three children), but they actually live with their mother/my ex right now, and that's only about 10 minutes away from where I live. When we were first divorced, they stayed with my ex 4 days and nights each week (by having them more than I did, she claimed their tax credits each year) and with me 3 days and nights each week. That made things a bit hard on our children as far as school, and homework, and where to leave their clothes, etc., etc. were concerned, and now they reside solely with her.
Anyhow, I did date someone for 2 1/2 years after my divorce, but that was mostly a long distance relationship. She was from another country, and although we video chatted for hours every day, she only came to America three times during our relationship, and she didn't meet my children until her third time here. She and I had discussed marriage (I was moments away from buying an engagement ring that I had picked out), but I would have never expected her to be some sort of "mother" to my children (they already have a mom, anyway).
Anyway, she made a crack about my children one day, and that was the day that I broke off my relationship with her. Again, I would have never expected her to be any sort of "mother' to my children, but I wasn't about to tolerate any disrespect towards them either.
That's about all I've got...