That one massive

line alone would have decided it for me. Threats are a no-no.
That didn't just sound like a business-type NDA, more like a very controlling life 'NDA'.
As others have said, go with your gut feeling and tread very carefully.
hmmm, sounds all a bit P Didley to me.
Why does he want people to sign NDA’s in personal relationships, sounds like he gets involved in risky or shady behaviours that he doesn’t want made common knowledge once the relationship ends and to be brutally honest, it sounds like it will at some point.
And where does that lead. There might be situations you are put in that leads you to feelings of guilt, anxiety, depression.
Then you may end up with an overbearing weight that you need to get off your chest, yet you can’t talk to anyone because of the threat of making your life difficult, and anyone that might approach you questioning your relationship with him will make you wonder if they are flying monkeys, and then you end up with feelings of paranoia. So your health could suffer.
You don’t just find $20k down the back of a sofa, all of those dollar bills will have strings attached.