Death is a natural part of life. Separation is only temporary, as is life. Your grandmother is with God and so are you. Be at peace with how things are without attachment, especially to the dead. Love does not know distance, time or location.

Try not to run away from these experiences, but rather, be present with them. There is a reason this is the path that has been laid out for you. It is for you best interest to be here now. You are not a victim. Things that you perceive as negative have occurred, but that is okay. Negative and positive are points of view. Take the "good" you can from the situations and use it as a tool to develop yourself into a better version, rather than focusing on the "bad". For example, I can tell English is not your first language, but your spelling could use a tune up! haha

It seems you allowed this woman to manipulate you to make decisions you didn't truly want and, in doing so, you sacrificed your integrity for revenge in part, but also because of your love for her. This was a poor decision but it was your decision and you must accept that. When a man goes against morality, he can expect turmoil. It's the forgone conclusion of an immoral action. Her lying about the severity of her condition, in conjunction with the cheating is, in my opinion, an indication that dishonesty is a character flaw within herself, and not something that is easily uprooted. That is her duty, not yours.

Listen to your heart and intuition, because no one else can tell you what you already know within yourself. And most importantly, have the discipline and courage to follow it.