Lots of people look to esteemed director Woody Allen as the go-to for seemingly inappopriate blended family relationships. It's gotten to the point that "the heart wants what the heart wants" can pretty much cover any indiscretion or unbecoming erections of the male OR female variety. Frankly, The Voice of God, Morgan Freeman not Metatron, has grabbed the lead in that depart and hopefully will be the reference point going forward. That being said, a woman in Merry Olde England has something to aspire to. 4 Strangest Celebrity Family Relationships Ever
Per Mom Logic, a "bird" met a "bloke" and they fell in love (or whatever the closest approximation of that feeling is). The bloke (Andrew) had a son (Ben) from whom he was estranged. The bloke and son remet via Facebook, of course, and became friends (or mates, if you will). But Ben also met the bloke's bird (Dawn) and a year later they became lovers (or mates, if you will).
Naturally, the bloke was very unhappy about the arrangement when it became known to him. Most of us would be pretty disappointed if our wife was doing it with our son and from more than just an Oedipal standpoint. Infidelity hurts and because you don't want your son dating someone who has such bad judgment that she would have an affair with her stepson because that woman just may end up dumping your son and having it off (if you will) with the son's best friend. And this obstinacy on the part of the bloke eventually did break the couple apart and drive the bird into the arms of "estranged son's" best friend.
How awesome (scale of 1 to 10) would your 18-year old step-child have to be for you to date them? For me, he/she would have to be at least a 4 or 2 if they were twins. Jokes!