Messed up..........help?

hey all, this is my 1st time here :) ok here goes....this is one confusing situation. let me start off by saying am a bi male, married to a great girl, she knows and is totally cool with it. and am also a soon to be daddy to a baby girl. but the thing is my wife's got a hot bro who's 23, married with a 3yr old boy. and am having really strong feelings towards him and at times i picture us as a couple living together, i told my wife and she says she understands my situation and is even ok if i make-out with him. yea i know its crazy. he and i get along great and he's cool to hang out with. but since lately ive been getting really strong urges to kiss him when he's around....and he's always around because they live next door. but he's straight and has no idea of my sexuality since am straight to the world and am not the feminine type in any way. so it freaks me out wondering how he would react towards me if he gets to know. but we got mutual friends who are gay that comes over and he makes gay jokes and seems comfortable being around them....i mean he's not homophobic. and he had kissed one of his male friends in the past as a dare. so what should i do....should i take a risk and make a move on him? bdw am 27 and my wife's 20. thanx in advance