You can never talk to a person to play gambling just for fun only and no hidden agenda if money is naturally involved in it, They will always tend to target that desire to win for money, You can not blame them that is the human emotion and playing with human emotions sometimes cover our judgment and decisions making, That is up to a person on what kind of approach he will do in playing gambling, But I really think you can give advise when you had a relationship with him or her,