This is rare that both testes have been undescended and the important thing is that you and your parents didn't know about that up till this age of yours. Well if it has happend, then the both of them were destroyed in the tummy. One has been removed as per you have informed us in your quarry. Where is the second one! search for that. See could be it is in Scrotum, if it is then don't worry you would be able to become father. 

However:

If not......................

Then sorry. Medical science has limitations. 

You may go then for adoption.

There are many people who don't have children. Man can't fight against nature. Try to be happy and spend satisfied married life. Counsel your wife as well in this regard. May Allah Help you and also those who are laking of offspring.