Welcome TellMe. 

You are ok!

It's good that she opened up to you with some honesty.  Just because she is Bi doesn't mean your marriage needs to end.  It doesn't mean she will cheat or find a new lover or leave you.  It does change the dynamic of your relationship a bit and can add some trust issues as you get used to this new revelation.  But a person can be Bisexual and remain in a fully committed and healthy hetero marriage. 
So this is my hope for you. 


I will give you a warning though.  In my experience on this board, most of the stories I hear involve a slow admission where the spouse claims to be bisexual at first, then eventually admits (or proves by action) that they are actually gay/lesbian.   They think the bisexual admission softens the blow and takes away their guilt for lying about themselves.   I truly hope this is not the case for you.   If you wife demonstrates a healthy sexual appetite towards you, then I would feel like bisexuality is likely true.  If you have an unfulfilling sex life and she doesn't show interest or ever initiate anything, then I would be concerned that Bi is actually Lesbian.