How to make sure ,to be partner won't turnback after getting the lead

We are planning a start up website to sell few products which are available locally but have quite demand on other places.

Here to outline I have the following experience:

1. Strong Technical Expertise

2. All the Suppliers information (Not available on website)

I do not have much experience in Sales or Marketing but my proposed partner have :

1. Around 5+ experience in sells and marketing.

2. Not exactly Client , but have the person who can help us sell those products at another location

So the buttom line he has the Sales and Marketing info where as I have the supplier contacts and Technical expertise.

Is it normal to think that he may use my info for advantage and I will be left out of choices?

How do I keep this things in hand till everything is signed as an agreement. Though we are not very close friends but still know each other well.

Shall I provide him the info only after legal agreement? But saying so feels awkward!!!

Perhaps you should start searching this site and Google for founders / partners who have run into problems with their previously trusted colleagues! cf. Divorce.

The fact is that merely raising the subject of legals can get the response "but don't you trust me?", and with someone you know it feels uncomfortable.

It's not about trust - it's about common sense and business - you both need to protect your joint interests before you get busy doing. (Once you're off and running with the day-to-day of building the site and business you'll most likely be too busy for legal details and may make poorer choices.)

So get the company, shareholdings, vesting, and other legal details sorted, then build your business.