Thanks guys for the valuable suggestions and concerns. I understand your feelings.

She was the one who ran away from the relationship with some purpose and opted for the divorce herself. Actually, she was already in some sorts of on and off relationship with some guy before getting married with me and I heard from some very relaible sources that she had been enjoying the company of some guy right after seperation with me.  Perhaps that was the reason why she tried to fight with me and opted out. For your knowledge, I myself tried hard convincing her not to go for divorce at those times for our son's sake despite knowing that she was not faithful wife.

That time during divorce process she did not even want her son (actually my son) with her, and did not request the court either. But, sometime later when she might have realized that she did a blunder perhaps because her relationship with her beau got worse or terminated (I have solid proofs that she had some guys at some different times before marriage with me and she herself even told me about it), she is trying to improve her relationship especially with my family and my son and woo them. So, recently from last 4-5 months she started frequently visiting my family to see our son (she used to ignore or neglet him during divorce process and even did not want to see him about 5-6 months that time)  Recently, she even told me that she is having a living hell over there and would like to come to Canada.

Forget about her, she is not an honest person. She will futher cheat me and ruin my life if I allow her to come to Canada and join me for the sake of my son. But, I already informed Canadian authority about my divorce and requested them to stop her from entering Canada if she produce my study permit claiming that she is still my wife and she was just vising her husband.  

My son is happy with my family and they love him more than anyone or anything else. He calls me almost everyday for about 2-3 minutes from home on the days I do not call home. My ex can visit our son whenever she likes and she should be satisfied with the visitation rights. And you know step mom is nice when you are nice. Step mom do not behave well when her own kids do not get enough to eat or to wear or to have good study, etc. But, we will have enough here in Canad so there will be no bone of contention between kids or between husband and wife or between son and step mom. So, I am sure my son will get enough care and love from his step mom-to-be.

Thanks again, I sense you guys. I knew reconciliation was the best way to go at those times despite knowing the fact that she was not an honest woman, but still unfortunately that did not work.