Every second person has similar story or what? However, the best thing is, we have to accept the truth.

I'm writing some years of my past. I'm not a victim but some around me are.

Time 1: I went to KTM from Chitwan for US process. Stayed in a "room" in a flat shared with an engineering student (say Raj) and his mom originally from a Terai district. I used to eat in my uncle's dera, few buildings away. Uncle's gharpati's daughter was "fuchhi", a good SLC student eager to go to US.

Time 2: I m in US, who cares what's going on in Nepal?! Fuchhi added me in facebook in 2007, now already finished +2, needs help about US colleges. I gave regular generic hints, as everybody else, she too came somewhere. She called once and then nothing else.

Time 3: I graduated, and got a job in another state. It happened to be in Raj's place. Raj was then a grad student with a pregnant wife. I got a few free dinners. After a few months fuchhi wrote a facebook message that she is transferring to the university near my job. She finally came but Raj and 'fuchhi' didn't seem to know each other. They are from Kathmandu where living in same neighborhood doesn't mean you know each other- I thought.

Time 4. I went to Nepal. Had to stay in my uncle's dera (fuchhi's home) in KTM for visa stamping. There I learned a story related to this thread's issue. Raj and fuchhi had an affiar. So deep that fuchhi got pregnant. Raj's mother was really caring and immediately talked to fuchhi's parent about marriage. However, because the saits were little farther, they decided to abort at that time. They aborted but Raj and his mom disappared suddenly. There were hearsays that Raj got married in Terai and went to the US with his wife - which was true.

Time 5: I came back to US. Told the whole story to my GF. That's disgusting, really isn't it?

Now, my GF wants me to never speak to Raj, but we can't ignore him, it's a small Nepali community here. Everybody (except ? Raj's wife) knows about the past but we cann't talk about it.

So, what will be the best other than just keeping things inside and to never speak about it again. Everybody has a life.

I saw some of guys are blaming girls in US in thread where we are talking about girls in Nepal. Guys using sajha deoesn't mean posting everything in everywhere.
I think some are NAYA BUHARI in sajha, so they dont have any idea on problem and post whatever they  want lol.

patalikopoi,
You are just assuming that your wife had physical affair with her bf and you are not sure about that. She could have lost her virginity while playing with machines. As long as she is committed now, I dont think you have to leave her , like the facebook user has posted below  .
Lets say you found out she had sex with her ex boyfren and you divorce her.  Have you think about what  will she  do afte that?
If she get married with some one after that,  you probably will be ashamed coz some one marries her even after knowing that she was divorced ( forget abt sex). If not, she will be devastated coz maarying again in Nepali culture is still rare and you may find yourself guilty later. 
If I were you , i wouldnot  try to raise the past issue. just dont let her do anythin stupid now.  There is one saying in nepali but I dont know exactly how it goes , but the summary is "if you are too curious, you will find terribly wrong thinng that you are not supposed to see/find". 
I understand the situation you are in is very complicated. You do not want to stay with her, but the other things around you do not let you leave her. We, as a sajha user are just giving you our opinion of what we'd have done if we were  in your place but the family/culture one was grown  makes a big difference in making decision. So analyze all the inputs from here, but dont make your decision totally based on the sajhali's input. This would be one of the very important decision of your life and if you make mistake , you can not do anything other then to repent on that. You cannot blame sajha users on that , and even if you do , that will not matter us or make any difference.
Think carefully and  make wise decision so that you dont have to regret again on your decision.

Thanks guys for all your advice, some of the comments and suggestions are what i was also thinking. My point was not just having relationship and losing virginity, my point was having an affair sexual as well as love whatever you say and trying to hide it. Keeping one person as a backup and kicking his ass when you get another probably the better. I didn't like that oppertunistic behavior.
 Knowing that you guys will say thisis america it is not a big deal i already told i am grown up in Nepal and i still belive it is not completely gone that wild. Everythingis measured by social norms, somebody who can take the risk of social norms and lies is not trustworthy, that was my real concern. And belive me the difference between your imagination and rality always hurts you. If you were clear and you accept it, it isokey this is your fault but being lied and betrayed is something you could have avoided. I caompare this to the behavior of Wolf.
Thanks any way. This is not just my problem, it happens to many nepalese but some can accept it some live hard with it and some quit the relationship. I was thinking

Go back to Nepal.