The partnership question is always a tough one. It can be very difficult to let go of control of the company, even when it is painfully obvious that the chances of success greatly improve if you do.
Also, not every opportunity is well suited for partnerships. What I have done in recent years is to mentally take myself out of the company and take an objective look at what really goes into running the business. Find the key roles, whether in sales, accounting, management, etc... If you are not an expert in each role, or the role could be cost effectively outsourced, the partnership/outsourcing is a good possibility. Also, try to take a detailed look at many different types of businesses. For each one, try to get a solid mental picture of the team it would take to run the business effectively. Once you do this enough times, developing plans for strategic partnerships becomes second nature.
Finally, if this your first founding venture, treat it as a learning experience. Rather that getting depressed when setbacks occur, pat yourself on the back. You're learning much more then you ever would in a 9 to 5. Also, no matter how it might seem, this will not be the only business you will ever start. Statistically, you will not hit the big one for 3 or 4 more ventures. That doesn't mean you will fail, you just need to look at the big picture. Treat each business as if it were something you can learn from and create enough value to put you ahead of the game going into the next venture.
And finally, cheer the f*ck up. It's only life. (I wish someone had said that to me last time I was in your shoes)
"Keep what you have by giving it away" Marc Katz