Whoah there, information overload, mate. Let's try to narrow it down a bit.
First - what the bloody hell happened with you and Dennis? I didn't even know you knew him.
All right, I know a little bit about recovery, we've a few patients who had some addiction issues as well as spell damage. Have you ever thought of starting a group for witches and wizards? I know there are quite a few with issues, especially any who've had previous trauma.
It sounds to me like you've more issues than whether or not to shag Justin. Have you been to see anyone for help on this? A counsellor of some sort? Maybe I could refer you to someone at St. Mungo's if you'd like. I've known you too long so I'd be too close to be objective.