Robert Griffin III's Friends Say 'No Way Wife Was Blindsided'

Robert Griffin III is telling friends ... his wife was NOT blindsided by his decision to pursue a divorce -- insisting their marriage has been on the rocks for two years.

But it begs the question ... why would the couple then buy a house TOGETHER in April?

As we previously reported RG3's wife, Rebecca Liddicoat, was devastated over a Cleveland.com report that Griffin was in the process of filing for divorce ... and has told people she was "blindsided."

But our RG3 sources are saying BS.

One source extremely close to the QB tells us, "They have been working on their marriage for the past 2 years. Things didn't get better. They have been separated since January."

"Robert decided to separate while pursuing a divorce, she was not blindsided by his decision to go through with the divorce at this time."

"All he cares about is being a great father to his daughter moving forward."

But TMZ Sports has learned ... Robert and Rebecca bought a house together in April. And according to the deed, filed on April 14th with the recorder's office, it includes BOTH of their names.

Our RG3 sources say he bought the house for HIMSELF only -- and there was no intent to live together.