Been there. What you are experiencing is totally normal if you're relatively new to poly and it will help you decide if it is for you or note. When my wife goes on a date with another man or spends the night at his house after they have dated for a while. I get the butterflies too. It can be exciting or wrenching. But they are emotions and you have to ask yourself where they come from - insecurity? jealous? And deal with the root cause. These are fires that burn away all the bs that we tell ourselves and reveal what is truly inside you and the core of your relationship. But if you want immediate relief - I would agree with the others, DISTRACT yourself! Go hang out with friends or see a movie. And don't imagine what they are up to. Truth be told, whatever you imagine they are up to is going to be a lot more interesting than what they are probably actually doing. Good luck!