not only the Titanic would have been effected but the fame that both Olympic and Britannic rode on the coat tail from Titanic's sinking would have never existed and they would be likely unheard of by most. Many safety standards would not have been enacted for another

as for the senerio that by chance we are refering to Rose then I would suppose that Rose would have married Cal for his money then divorced him and run off with Jack only to cheat on him also. Jack not being able to handle the stress would threaten suicide by jumping off a tall building but saved by a strange beatitful woman who said "If you jump, I'm just going to watch."