Ex-LGF erred in AoC of Tasmania

A Tasmanian put up a video camera in his kitchen to detect evidence of paranormal activity - and ended up detecting evidence of paramoural activity:
http://www.themercury.com.au/article/2013/05/20/379630_most-popular-stories.html

It was his womanfriend and a mother of one of his children, the WF aged 28, with another of his children, a boy aged 16.

The woman claimed she thought sex with 16 year old was not against law in Tasmania.

And she had compelling reasons to think so!

She had been in a relationship with the man for 11 years and known the boy since kindergarten.

Meaning that when she got together with the man, she was a minor of at most 17, possily 16 depending on months, and he was a father in custody of a 5 year old.

It is eminently sensible that if a father of 5 year old does not commit a crime by loving a 17F, the AoC must be 16 or less and therefore the 28F also does not commit a crime by loving a 16M.

How about your present or future LGF-s?

If you get together with a 17F or with a 7F and she then consents - would you hold her bound to be faithful till death does you part, as you could with a 18 year old bride who gets second thoughts at, say, 48?

If you get together with a LGF, and she goes on to fall in love with somebody else when she is 30, or 13, would you disown her as you would do with an ex-wife? Or, considering that she has been raised by you for years and may have been alienated from her birth family, would you feel responsible to support her, her beloved and their children as you would with your birth daughter and her lovers and children?

Also, how about stepfamily incest?

Would you prefer your GF to fall in love with a complete outsider, or a close relative of yours who already lives with you?

If your wife cheats you with a stranger, you can tell her to get out and go live with her lover. If your wife cheats you with your own son, the problem is that your home already is your son´s home, and you have to be ready to have an unrelated girlfriend/daughter-in-law and her baby moving in with you anyway - so your exwife can quite reasonably demand to stay in your home as your now daughter-in-law, and you have to put up with her loving someone else in your own home.

On the other hand, if your wife cheats you with a stranger, considering she is unrelated to you, so is the baby - you are becoming a mere stepfather without your consent. If your wife is in a relationship with your birth son, you are assured that the baby is your relative - if not your child then your grandchild anyway.

So... For the girl-lovers who actually have beloved girls and have a non-abstract dream of getting together with her: how supportive would you be willing to be to her if she desires to move on after some years?