VENTING on Cheating

I have ALWAYS had a low tolerance for cheating. In HS my boyfriend lost his virginity to a random girl at a Mizzou party, and I still think Mizzou girls are slutty. We broke up and ironically 2 years later I was crying on his shoulder when I found out my dad was cheating on my mom. I think at that moment he probably realized how much he had hurt me and that he was a good friend of mine who I trusted. We still talk occasionally and are pretty good friends for being my "first real boyfriend" 3 years after Adam cheated on me, my boyfriend at that time would cheat on me and be one of 8 possible fathers for a girls baby. Both of those relationships are actually really irrelevant to this blog. When I was 16 years old my father began having an affair with another teacher at his school, she was recently divorced and when married was a friend of my parents who came to a few parties at our house. My dad moved out and served my mother with divorce papers when I turned 18. We are just now 6 years later beginning to have a decent relationship, he has called me on the phone several times in the last month and visited my house twice in a year, the third time to Springfield in my whole college career. So I have had a huge problem with people who cheat, more so women than men. I'm not sure why women bother me more, maybe because I assume this woman came on to my dad, maybe because I think of them abandoning their families.
So tonight when we went to Piano Bar for my "free" party and Blake started inviting his work friends I decided I needed to leave. Blake works with a girl who was cheating with a guy at work. She was married and he had a pregnant wife. Her husband found out and divorced her, he packed up his family and moved to Columbia to get away. Blake is out of town a lot for work at other banks and almost always with 8-10 other co-workers. So it was "easy" for these two to have an affair because no one questioned their being out of town together two weeks a month. I said hello to her and than waited 5 minutes for Blake and another guy he works with to have her chug 3 beers before telling them I had to go home because I have to work tomorrow. Blake is on his home to get home if he does at all... I couldn't even stand to look at her because I had known what she had done, to her husband and her "boyfriends" family.
I also know of another guy Blake works with, I use to work with him at the bank. J's wife was having an affair (or maybe still is) with her boss. Her boss got divorced and left his wife and 2 kids. I am sure that J has to know but than again his wife still works for the same man and is still together with his wife... I give him serious props for being able to stay with her if he knows because I know that I could not do that!! But how easy was it for her to cheat, her husband was out of town 1/2 the time and she just had a small child who didn't know the difference. How sad!! I just don't understand how anyone could do that to someone they "love" and especially to their family. I have seen first hand how someone cheating effects the family. Until the age of 16, and even until my mom told me my dad was cheating, I thought my family was perfect. My parents fought but not a lot and never over anything serious. They were always really affectate and loving towards each other, I never once thought my parents would get a divorce until the day he left. Even to this day I will always question my relationships because if after 18 years of "happiness" a divorce happened....how long do you have to be married before it's "safe?" Is it ever safe?