WOW!! at least your hubby took his own initiative to confess to you!! i think it takes a real man to do that , and in my opinion, he prolly truly loves you to tell you the truth. Its prolly eating into him n hes suffering in guilt. otherwise he could have kept his trap shut and just continue to keep it from you.
and its just a one night stand? i assume no affair not feelings...
it will def take time fr you to recover form this and to trust him again. you guys can consider seeing a counsellor to help you recover from this.
its very tough fr you, but if you still love him n wanna salvage this marriage than you will have to face it, deal wit it and get over it. and imo do salvage the family..