I always thought this song was talking about a girl who loved someone who didn't love her back, so she made jokes about his future love life to distract herself from the fact that he doesn't love her. The intensity and repetition of "I love you" conveys she really loved him but it was impossible for that love to be returned. To make herself feel better she made assumptions that he would have a superficial marriage with everything perfect but real love which she felt for him.
I always thought this song was talking about a girl who loved someone who didn't love her back, so she made jokes about his future love life to distract herself from the fact that he doesn't love her. The intensity and repetition of "I love you" conveys she really loved him but it was impossible for that love to be returned. To make herself feel better she made assumptions that he would have a superficial marriage with everything perfect but real love which she felt for him.