My husband never told me about his son

I have been married to a very wonderful born-again man for three years now, and we have two children. About four months ago, he brought home two boys, 7 and 10years old, and said they were visitors from the village.

I kept wondering why one of the boys shared his exact names. However he was cagey about it, but later said he was a son to his elder brother. But my husband kept paying school fees for the boy behind my back, visited him at school, bought him all the requirements and I kept wondering why this boy's father, was not footing any bill for his son, nor visiting.

On further snooping, it dawned on me that the boy who was right under my nose, was actually my husband's first born and heir.  

He has been a great husband. I want to leave him and start afresh because had I known about the son, I would not have married him.

When I look at him now, I do not see the man I married but a liar who kept a huge secret from me.

I have lost all trust in him and cannot bear sharing a bed with him anymore; I have been sleeping on the floor for the past few days since I made this very hurtful discovery.

What should I do?

Annet