Like a saying, "if you want to go fast, walk alone. But if you want to go far, walk with other people."
Collaboration in business is a good way to give your business a boom in a short time. But I'll advice anyone who wants to go into a business collaboration with another person to always have a legal agreement. Invite your lawyer, let the job description of every party involved be spelt out immediately. This will go a long way to avoid stories that touches.