I'm guessing he just wants to settle down and have a family.

^ Or maybe he's just afraid that she'll end up thinking of him as a brother like ayu did, lol :P

If you want to have kids then it's always better to get married by 30. I don't think you should let the age gap between you and your kid get too wide. Although some hollywood stars think it's perfectly fine to stay unmarried and still have kids... To each their own i guess.

Other then that, maybe the girl was just the one for him. He felt it really quickly. For ayu, their relationship just seem to drag on and they got to a point where they are so comfortable with the status quo ayu even regards him as a brother but whatever. I never factored in nagase with ayu anyway. Ayu was solely ayu to me.

If he´s getting married a year after having boken uo with Ayu, it shows that he never loves Ayu at all!!!!! Piece of Crap!!!!