stay strong simon. speak to a counsellor if you need to. you really need to take off the rose tinted glasses and start noticing her flaws. find one or two bad things about her and focus on that. its just a silly crush. did you look up emotional affairs and the funny affect they have on the brain and the regrets people have?
do your research. also research the 9stages of love. your in stage 9 now with your wife (true love) and stage 1 with your neigjbour (infatuation). the only thing you can do wrong in stage 9 is take her for granted. dont do that
have you spoken to your wife about creating more romance in your marriage? put all this energy into saving what you already have. forget what could be with someone else
"Don't ask a question if you can't handle the answer".