Assassination Trivia

[RJNorton]

One author has written about the following scenario:

1. John Wilkes Booth was not killed at Garrett's. He got away after assassinating Abraham Lincoln.

2. Booth went into hiding.

3. Later Booth had an affair with a married lady.

4. The lady's husband died.

5. Booth impersonated the dead husband and became President of the United States.

Which U.S. President was really John Wilkes Booth (in disguise) according to this author's book?