To threadstarter, I hope you reconsider your decision to stay with him. I don't think anybody here will tell you otherwise. And please don't make this into a "you and me against the world" drama. Wala ka naman talagang "isusuko" because he was never yours to begin with. Let go of those "romantic" notions in your head. Ikaw lang din ang mahihirapan. Ano't ano pa man, ang asawa pa rin ang mas may karapatan sa yo. Tama yung isang sis dito, give him and his wife a chance to fix their marriage. Yes it's sad, yes you may think it's unfair, but that's how it is. Ibigay mo yung pagkakataon sa kanila kasi sila ang mag asawa. And don't forget, he didn't choose you. Whatever it was, whether it was fear of something, his sense of responsibility, or his conscience, whatever it was, yun ang pinili nya over his supposed love for you. That alone should tell you hind ka nya kaya panindigan.
You may not be a "full blown" mistress now, but you will be if you don't leave this situation. You are still in a position to turn your own life around, wag mo sayangin. You may say, how easy for other people to say this or that, when they've never been in my situation. Well, I HAVE been there sis. I was once a kabit. A real, no bullsh*t kabit. Believe me when I tell you, there is NO real joy to be found in that situation, no real peace, and no real, lasting freedom. At maniwala ka, this isn't your last, your only, chance at happiness. There are so many good things, BETTER things, out there for you, if you only choose to do the right thing.