No.
Relationship 1: Met October 24, 2003; started sleeping together November 8, 2003; started dating December 3, 2003; he said “I love you” March 29, 2004; I returned the sentiment.
Relationship 2: Met October November 8, 2003; started sleeping together May 12, 2006; he said “I love you” November 12, 2006; I returned the sentiment; we started dating as a result.
I think both of those were logical progressions of the “I love you.” If it had come more than a month earlier than it had in either case, I probably would have been weirded out and may have even terminated the relationship.
You may notice an odd coincidence in the above dates!