If you are this nervous about calling her ,she will be married with 2.2 kids and a white picket fence before you get up the nerve to ask her out to dinner.

OK i will probably take some flax over this reply but so be it ,,,,
Heres a thought maybe your husband is as bored as you , maybe he looks at other women with the same urges as you ,communication is what is needed in this situation ,you say hes your best friend so you should be able to sit down and ask him piont blank how he feels about your sex life , maybe it could be a two way street , you both go find what you need to fulfill your sexual needs or find another couple to swing with ,, its 2008 not 1950 and their's a lot of people who have this kind of marriage and have been togeather for years , i agree with alot of comments here about lying ,cheating and being unfaithful ,But at the same time living a life of unhappiness will eventually end the marriage .Talking and listening honestly with each other can probably solve you problem and save your marriage .