Sounds like a potential sociopath with the knife throw .. ditch the guy! he could kill
I had a different impression: he's a type of bully/dominant type of guy that wants to get his way, and he sees someone (the OP) who is definitely on the submissive side. (note: I'm talking in a general sense of 'power balance', not in a sexual sense)
Consider the knife-throwing incident: a guy who is 100% sober says "this knife is dirty", then throws the knife across the room into a sink, where the homeowner is standing. The homeowner's reaction: "Do you need a sharper knife?" No disrespect to the OP, but this is not a healthy response to someone throwing a knife at you, and potentially hurting you, and/or damaging your property. IMO, the guy was simply asserting his dominance in subtle ways - because look at what happened next: the knife thrower tells the homeowner to "get away from me" and "go in the other room".
Which she then does, as he orders her to.
The OP allowed someone to throw a knife at them across a room, then reacts in a calm, nonchalant manner, and then follows orders from the knife thrower on what to do in her own house. The guy is doing this because he likes to exert his dominance. And he gets away with it.
Same with the multiple comments of "He has let it be known if my husband was gone he is interested." Who says that MULTIPLE TIMES to someone that is 'happily married' - and who is also a friend? That takes quite a bit of arrogance/disrespect to say that multiple times to someone who is married. Unless they are trying to plant thoughts and seeds in someone's mind that they know they can boss around (see above example).
Also, I'm willing to bet that if you heard your husband say multiple times to your best friend "hey, if Teacher Terry weren't around, I'm interested in you," it would not sit too well with you.
It's good to see you severing ties with this guy - just some thoughts to reflect on and be aware of in how you interact with others. I used to be in an unhealthy submissive role in a few bad relationships, but as my life improved and I became more aware of it, I was able to correct it and enjoy more healthy boundaries in my relationships and interactions with others.