I'm male on testosterone therapy and my estrogen is double what it should be?

Go see your doctor. The good news is that your doc checked. Before you look for more drugs eg aromatase inhibitor, in a domino fashion, ask yourself if you've noticed any side effects from excess estrogen. If not, you can take a wait & see approach. Or take less testosterone more frequently (that way you won't waste excess testosterone). Or change your method of therapy. But all this must be discussed w/your doc.
Male estrogen. Testosterone may be converted to estrogen by an enzyme called aromatase, which is produced in adipose (fat cells). This can be treated - I suggest that you consult a urologist who is experienced in managing men with low testosterone. .