Where can I sue my wife for bigamy?

In whatever court has jurisdiction, probably where you both live. Or where you live, if you are apart.

However, has she been arrested, charged and convicted of bigamy? For it is a crime. If she has not, you are unlikely to win a civil judgment against her.

Consult with an attorney on this one. Such things involving marriage can be very complicated. The more so if there is more than two people involved.