If this is YOUR attorney, he would be required by ethics to advise you of any material fact that could affect your case. As such, I would find it very hard for your attorney to keep facts from the deposition from you.
My opinions:
1) Assuming you (your attorney) called the deposition, YOU are paying for it (either directly or through your attorney). You have every right to DEMAND information from your attorney.
2) And since you are paying for the deposition, you area also paying for the transcript (and/or video) of the deposition. You have every right to DEMAND full disclosure of what you are paying for.
3) And even if not, the transcript of the deposition, once admitted is public record. Again, you have every right to read it.
Finally, you certainly have my curiosity up... what do you suppose is 'so secret' that your attorney is trying to hide it from you???? And is it relevant to the case at hand (if the Plaintiff's attorney didn't object as to the question during depo, I assume it is relevant).