2 things,
first you said that the dursleys where died and now their alive. secondly, why are you asking for wifes if you have harry as ethier gay or bi.
Author's response
Thanks for pointing that out to me about the Dursley's. I had some issues uploading the 2nd chapter and uploaded the old version instead of the newer one.
In regards to the second point you brought up, Harry is slightly bi but mostly straight. He started the affair with Severus to get him on his side and to have something to hold over his head in case he decided to bail out.
At this point the blackmail isn't necessary and won't be needed in the future. Harry knows that Severus can be a powerful ally, for one thing he is a Potions Master and can brew all sorts of things and having a Mastery he has the ability to alter existing brews. For another Severus is a dark wizard and knows things that Harry would have a more difficult time finding someone to teach him, he has also served under Voldemort and therefore has some idea of the Dark Lord's personality and the personality of some of his older Death Eaters and their fighting styles.