Is David's Love for Jonathan erotic? The following verses about David and Jonathan's relationship have lead some to say their relationship was more than platonic. Is there any reason to think that was the case?

Now it came about when he had finished speaking to Saul, that the soul of Jonathan was knit to the soul of David, and Jonathan loved him as himself. (1 Samuel 18:1, NASB)
Then Jonathan and David made a covenant, because he loved him as his own soul. (1 Samuel 18:3, ESV)
I grieve for you, Jonathan my brother; you were very dear to me. Your love for me was wonderful, more wonderful than that of women. (2 Samuel 1:26, NIV)
In your question you seem to have overlooked two very important points

1st Samuel 18:1  KJV


  And it came to pass, when he had made an end of speaking unto Saul, that the soul of Jonathan was knit with the soul of David, and *Jonathan loved him as his own soul. *


In the "soul of Jonathan was knit with the soul of David" the important point here is the word knit That word in the original was:

קָשַׁר 


  qashar (kaw-shar') v.
  1. bind (up), (make a) conspire(-acy, -ator), join together, knit, stronger, work (treason)


In today's vernacular that would be said " that they had become Soul mates".

There are no connotations of any physical relationship the word used for such a union is:

שָׁכַב 


  shakab (shaw-kab') v.
  1. to lie down (for rest, sexual connection, decease or any other purpose)
  [a primitive root]
  KJV: X at all, cast down, ((lover-))lay (self) (down), (make to) lie (down, down to sleep, still with), lodge, ravish, take rest, sleep, stay. 


So in answer to your question is no it was not erotic. 

For the record how can a person have an erotic encounter with his soul?