Harry Potter/Sirius Black question?

If he seemed one dimensional or not too interested in life, it prob because he has wasted the good part of his life in prison and of his three best friends, one is dead, one is lliving a half-life as a werewolf and the third has turned traitor. Seems the only good thing in SB life is Harry. Had he had time, he would have made a new life for himself, but being on the run from the law, and only having escaped for a few months, he didn't have a lot of projects happening. Perhaps he would have got it on with Nymphadora had he lived...