I find it unbelievable that she didn't recognise her husband and I don't like that she wanted to sacrifice her love for her duty as a wife but the movie is my guilty pleasure and is funny.
Not sure that she really was in love with Raj... He may have given back the joy of life to her and she was sensible to h i s love for her... but what Suri did at the fair explicitly for her was something that touched her more deeply as she had expected ...with everything else he did before - as Suri - she finally could see his love for her and that h e r happiness was his primary goal
(which was what also Raj showed her)... but with two men - one having married you and caring for you - who showed you their love, why not choose the one who already is your husband???
In my understanding, this movie was quite intelligent - and v e r y touching. When she finally started to r e a l l y see her husband, Raj definitely got the role of a friend and not of a lover... fine to me that she got both in one 
10