I actually rather like this...the Slytherin-esque way that Harry handled Ginny was quite original. He could have wailed and denied her but ended up getting his child, a faithful wife regardless of what she wants, protection from her ever getting her hands on his money and he still gets Severus. He finally grew into his Slytherin side. (Of course living with the quintessential Slytherin must help.)
While the ending was sort of sad it also wasn't, for me. I thought at first that Harry had been given a love potion or had left Severus...the alternative was much better.
Great job with this. Very original! (Of course I can't stand Ginny (and I don't like her mum much either) so they all seemed very in character here.)