Should I wait for him to leave her for good?

At my son’s baseball tryouts, I met a good friend. He was there with his son. We found that we also worked at the same plant. He was married and we were all friends. October of 2006, he informed me that she had been cheating on him for quite some time and that they were thinking about splitting. He was distraught and lost. I was there for him as a friend and never tried to sway his feelings. We both knew that there was a slight attraction between he and I but respected his marriage. Finally in December, she walked out on him and their children to go live with another man. He and I started dating about a month later. We bonded so quickly. We were looking for the same thing. Apparently she had cheated on him the entire 21 years of their marriage but he was so determined to keep his marriage he just pushed his pain behind him. I have a really hurtful past with men as well. She started doing the partying of a single woman. Then as soon as she realized he was moving on with me, she started tugging hard at his heart. He and I started making plans together and I truely felt that we loved each other. Well, now he is so confused on what he wants. He says that he doesn’t want her but doesn’t know how to give up 21 years. He feels that he is a failure if this lengthy of a marriage ends. She was never faithful to him, she put him down, and didn’t believe in him. Their divorce was supposed to be finalized next week. As the date got closer, he became more distant and moody with me. Out of the blue, he decided that he couldn’t finalize their divorce and she instantly jumped at the chance. She immediately moved her things back in his house. And why not? She didn’t have a job and needed a security blanket. He is so torn. She has been back in his house for a week and they are already fighting. I know he loves me. But how do I make him realize that just because there is 21 years of marriage there, his self respect and happiness should prevail. She has told him that she couldn’t ever guarantee 100% that she wouldn’t cheat again. He walked away from me and I am so distraught over this. Should I walk away from the man I love to allow him to decide if I am the one for him? Do I just sit and wait?