I think you are better off telling him how great OW is, how much happier she's going to make him and how thrilled you are that he has found someone to make him happy and you know you will find the same.... That there is someone else out there better for you who is going to make you happy.... And just tell him "Life is great!" and be VERY HAPPY.
There is no arriving, ever. It is all a continual becoming.
