The answer is, too often, the lawyers who you each hire to help you resolve the dispute, so while it likely make sense to see some lawyers -- and you each need separate ones -- try not to make the matter cost more than the value of the business.
You seem to be 50% shareholders each, NOT "partners" and thus the cororate laws apply. If so, you each own half the company which owns the name and other assets. I also assume that you have no written or other agreement setting forth what would happen "if something happened"?
In a situation like this you sometime can try to resolve it among yourselves, but recognize this is like a divorce.
For example, if you sell the business to a third party for $X, each of you get 1/2 of X. Or perhaps one of you may be interested in something the other is not. For example one takes the lease and name and the other takes the merchandise and cash in the bank.
Or each of you can make a cash bid for the other guy's half. Sometimes people flip a coin. The winner gets a firm offer from the other 50% shareholder, and 15 days to accept it. If he doesn't accept it, then the guy who made the offer can buy the guy who received the offer out at that same price. This tends to make the bid a reasonable one -- you give me $Y or I'll give you $Y. But that agreement needs to be done by a lawyer.