I've seen this as well but in a much later stage of running a company, a nearly done deal went south at the last possible moment and everybody got demoralized to the point where they wanted to quit. I ended up selling my house to buy everybody out, and it's been a pretty good company ever since.

Not everyone is made to be an entrepreneur you have to take your beatings and keep going, that is the only road to any kind of success unless you are a very lucky person.

I'd make a reasonable valuation of what you think the whole project is worth at this time, try to figure out fairly what their contribution is worth and then offer to buy them out if you can afford it, or, if you can't to take them on as silent partners and give them non-voting stock. The latter is a (nearly) surefire way to never get any investors on board though, you have to be aware of that.

Then, after that you go and work like the devil to make it happen.

If you can't afford it and/or you don't want to have them on board as deadwood I'd just walk away, and do something new.

About your 'black cloud' following you, this can happen simply as a series of coincidences, or it might have to do with the company you keep & pick.

That's very hard to comment on without knowing a whole lot more about the situations you were in, one thing is for sure though, if you want stuff to happen and to succeed then you'll simply have to shift over to the drivers seat, if you think you 'need others to succeed' you are not yet in the right mindset, you are seeing yourself as a victim or at the mercy of others. That needs to change for sure.

Maybe it's the repeated failures to get investors that did it. They might need to be reminded that the lack of investors is not necessarily a bad sign - audiences, unlike VCs, have nothing to lose by giving you guys a chance.