Met Life sold not even 1 share of stock for both me and my husband. i don't know how to figure out the cost basis?

The Brighthouse basis for ALL the stock received, including the fraction of a share, is 10.3635% of your MetLife basis.

IF you received your MetLife stock in the demutualization of MetLife THEN the IRS takes the position that your basis in MetLife is $0 and 10.3635% x $0 = $0.

IF you received your MetLife stock in such a fashion that you DO have basis in MetLife, e.g., inherited the stock, bought the stock, THEN

1. Multiply your MetLife stock basis by that 10.3635% to determine the basis for ALL the Brighthouse stock received (including the fraction of a share).
   
2. Divide the Brighthouse basis by ALL the Brighthouse stock received (including the fraction of a share).  That results in a "per share" basis.
3. Multiply that per share basis by the actual fractional share received.  That give you the basis to report.
4. Your holding period is the same as your MetLife holding period.  The MetLife holding period carries over th the Brighthouse stock.
   

Tom Young