if you realize that nothing is worth to hold on in your marriage, except kids, and kids are not the reason of marriage, you need to talk to your hu*****and. let both of you be free, it is just unfair to treat someone like that. don't think you did him a favor to stick around! he deserves someone trully love him and you too. when you sort it out, you should tell your "friend": you are free to persue your love. he might be scared away or he might be force to face his marriage. either way, it will be best thing happend to you. you will find someone you really care for some day. be honest to your heart, and don't try to just experience or out of control. sooner or later, you have to face it anyway.
p.s. i can't believe i am typing all these crap at this time of the day, if my lg at home, he'll think i am completely nut.