Dearest darling sweetheart couples. Please.
DO NOT TALK DURING THE MOVIE!!
A couple of comments on occasions where your beloved does not understand the subject, is okay.
Running commentary - NO!!

It happened in the second Lord of the Rings movie - those ones I really had to shush.
These ones were quieter, but it was still bloody annoying. I guess I was too chicken to shush them loudly enough.

Inform your sweetheart about the movie. Give him/her the back history BEFORE YOU GO IN.
Make them WATCH THE PREVIOUS MOVIE at home beforehand.

Don't make me listen to you when I paid good money for this!!
Bright comment from the LotR movie couple. "Those are the Bad guys." (Cue scenes of an army dressed in black, looking generically ugly.)
Well... DUH!

At least I enjoyed Xmen 2 for the most part. The Wolverine chap is perfectly cast.
No spoilers here! :) But for a fee, and a movie seat, I will sit next to you in the theatre and tell you what's going to happen next just before it does, in a voice just loud enough that the person next to me can find out as well. For no extra charge, I will also tell you where it's all leading, who the bad guys really are, and who's going to die.
BWAHAHAHAHARRR. *snerk*