The love of my life cheated on me and left me for this guy and I can't stop thinking about how bad it hurts. What do I do to stop these intense rushing thoughts?

Just keep in mind that you did everything that you could do. Its their problem if they're not contented.

Learn all about how adrenaline affects your anxious state. To understand is half the battle. Change your reaction to “no reaction”, not in the fearful sense at least. This is easier said than done, but as ridiculous as it sounds, try to learn to smile at these thoughts. Know that to give them no importance can break the chain of producing yet more adrenaline, by way of the anxiety they produce. Don’t fight the thoughts. Let them be there, quietly and with as much nonchalance as you can muster. Accept willingly and give them permission to be there. Engage in normal activity as much as possible when you have accepted the thought. Distraction will not work alone but will merely put off the inevitably of repetition. A nod of acceptance and then moving on with activity is the best way forward. Only you will know if you are truly accepting. Tell yourself that you are in control and your intrusive thoughts only mean something if you give them importance.

These feelings are normal considering the love you felt for this girl. This is something I have experienced. My long term girlfriend cheated on me and began dating another man a week after we broke up. There is no magic cure that makes the pain go away. The feelings hurt and you miss the way things were when you did not feel this way Find things that make you happy, reconnect with your passions and with time, These intense feelings will pass. It takes work and it’s tough and there will be days were you feel more pain than others. Remember, This too will pass