I am afraid I do not understand Olivia's feelings of hatred toward Patti and John. I think perhaps I agree with Yuka's comment of how she is like the cartoon/video game character lover. Perhaps if given time she will sort out her true feelings and realize that the George which resides here is not the same George, in a way, that she married. He is a much younger, unknowing of his and her future relationship, George. Though, personally, I could not see George marrying such a materialistic sort as she seems to project herself as being. But, perhaps I am just seeing things with my own eyes and not her own. So I cannot pretend to know what she truly thinks and feels for George.
As for Patti and John... I feel, at any rate, they are undeserving of hatred being sent toward them. John has shown me kindness by allowing me to help him in his new home. And Patti, though I have not really spoken with her, I feel she is kind as well. And if I cannot find it within myself to hate George for having a more-than-platonic relationship with my future husband... Why should Patti and John be so subjected to anti-feelings from a woman that will not be meeting George for another 10 years or so? Perhaps her eyes are simply blind to the love John and George share.
And the guide to true happiness is accepting that which is given to you... even if that which you were given is not what you feel you desire. She should be joyful for the fact George has love even if it is not with her. Perhaps in time, she will accept this and be happy for George and John, and cease to dislike Patti.