Greenblue - I want to make clear that I never have and never will suggest that an open relationship is some kind of cure all, or will work for many people.
I think your situation is somewhat unique in that your wife is bi, and that means she has very strong needs that can only be met by a woman. Yes, she can attempt to ignore those needs, but there may be a cost to her doing so.
There are numerous examples of people who are bi, who satisfy their Same Sex needs on occasions, but because they value their spouse and their family life, maintain a very healthy marriage. Perhaps if you examined that a little more deeply you wouldn't be so scared about it.
It is very possible that your wife will love you all the more knowing that you have come to terms with her sexuality, which she may well have been struggling with for many years.
On the other hand, it is just possible that your wife is actually gay, and is rounding herself down to bi. If that is so, she may never be ready for a sexual relationship with you. At that point you have to look at your life and figure out how to proceed. Could you be happy if she were seeing people outside your marriage and you were too? Is that something you would be willing to investigate?
bob
divorced in 2003 Married in 12/2005 born 1948 wife born 1958 divorced in 2001