I was toying with lust for some weeks now, and i started flitting with my wife's niece but she told me she wasn't interested. But the lust for her kept growing that my wife has noticed that something is troubling me.

I want to get out of it but I cant

What do I do?

and also a very big NO to yourself!! thought stopping is what you need to practice - every time an unwanted thought starts you tell yourself (audibly if neccessary-when you are alone anyway!!) NO-STOP!! and keep it up until you can control this....your wifes niece does not deserve this and good on her for putting a stop to it - doing that to a family member is just not ok!!! so take yourself in hand - never ever allow yourself to be alone with her or to ring her - just stay out of her space and get busy and do some fun stuff just for you and your wife - if you cant stop the obsessing -talk to your doctor - good luck

you going to have to distract your self. like going away with your wife for a while and make an extra effort with her. be extra nice to her and she will be extra nice to you. maybe your love for your wife will increase and on will be left for anyone else.

or even think of some bad points about this gal and see how that helps.