yo sup guys I had the same problem like you guys ive spend 50 hours of research my self in bp node
but i just found the way to put a dam music pause menu it extremly simple finaly lol
just loock at that pic Screenshot - c28b0d0932f836352ad0bfa71171792f - Gyazo
it should all fix yours
if u cant see the image ill descrybe it : in my event graph pause menu ive add ( Event Construct -> Spawn sound 2d ) that bring the music but for close the music i add in same widget (Event Destruct -> Fade out ) u onlly need to connect the return value from the spawn sound 2d to the target of the node fade out ! and there u go hahahaha
am mad at my self all that time wasted for only this **** lol