You said: "but in the business settings I do not share interests with my customers or my suppliers"
Oh my - you certainly do!
If your customers or suppliers go out of business, or even if their business declines, it affects you. So you are really a partner in the sense that you all must work together. You both must have mutual goals.
In a greeting card or personal message, you can use "partner" as a verb or a noun.
I am glad to partner with you in 2012.
I am glad to be a partner with you as we approach the coming year .
This kind of "partnering" is not the same as that in your financial agreement with investors or your business partners.