One of the time-honoured standards of the romantic world is the concept of having a back-up girlfriend or boyfriend, someone you're not so enamored with that you'll commit to a relationship but definitely cute and fun enough that you'll shag them on a week night.
A lot of females find it insulting to be reduced to the sum of their body parts and this outrage is volleyed around women's mags, talk shows, stupid TV series, chick flicks and hairdressers but somehow never in Ralph magazine or James Bond movies.
There's a simple reason for this: blokes accept it's the way we are, we move on, so should you.
This leads to the next golden rule, which can be tough to follow when you're running into your new girlfriend's dickhead, abusive, pisspot ex-husband: don't trash talk daddy.
It's just unfair, it's really not your business and it can cause enormous resentment in a child if you're slagging off their orangutan dad in front of them, even if mum is doing the same.
Obviously not rooting mum in a highly audible (or visible) manner is a good way to ensure you don't get off on the wrong foot with the kid, and most single mums I know are pretty scrupulous about not letting new men sleep over at their home until a fair way down the track.