If you have really been "lurking styleforums for a while" you would know better than to publish a photograph of a motor car and a dark one of a coat with parts obscured.
That is neither use nor ornament and no one will be able to make any comments - other than about your misplaced hopes.
Ask the man - if he is so vague he should expect questions. Secondly forget that suit (if that is not to charitable a word. Blue with a black shawl collar resembles something the band or a waiter might wear, certainly not a guest.
The suit will not be much use for anything else - the black trim is dreadful. Secondly if the girl demands you wear this or not that, dump her. You should determine what you wear and you should not even think of matching her - you are not bookends.