In a conference call to investors, Electronic Arts' Blake Jorgensen just said that Titanfall is, "for the life of the title," exclusive to Xbox One, Xbox 360 and PC. So the game is not a timed exclusive to Microsoft platforms.
Titanfall's Microsoft exclusivity has been well known since the title was announced at E3 but it was never definitively said that Respawn Entertainment wouldn't build some version for Sony consoles.
In a recent Reddit AMA, Xbox Live spokesman Larry "Major Nelson" Hryb avoided a question about the possibility of such a port. "As far as being an exclusive that's really a question for Titanfall—I'm not worried about it though," Hryb said.
UPDATE - While Titanfall is a Microsoft exclusive, don't bank on future games being part of the same deal.