Hi, I believe you are referring to the "horizontal ellipsis" (in the English language) character (i.e. #x2026;) "…" as opposed to "..."
This is a feature of Word, and InfoPath uses the Word settings. You must turn this off in Word.
This feature bugs me too and I've turned it off already. I can't seem to locate it in my Word options, so I am left to assume that it "was" in Tools | AutoCorrect Options. Scroll to the row for "..." and delete it (assuming that's where it originally was!)
I tried adding it back, and sure enough, after restarting InfoPath, it autocorrected again... then when I deleted it, it stopped happening.
Good luck.
Greg