Hi Moulib,

from reading your posts, I can see that your ex seemed to be able to spend more time (more than once a week) with this other girl, and if his other friend still has negative feelings towards you then your ex might be being persuaded to be with the other girl.
There also seemed to be a clash of egos between your ex’s friend that wrote you a hate letter and yourself, the issue seemed to stem from a mere lack of not having a proper introduction which doesn’t seem to warrant a hate letter.

Either way, your ex doesn’t seem to know what is best for him but rather the friends he is close to seem to know what is best for him, unfortunately. From the outside looking in you seem to be out of a relationship that brought you problems or ill feelings and if you ex has made up his mind then you moving on and embracing your own life and not chasing after him would be the best action. Leave your ex to find out if his new relationship is actually what he desired, as he and not his friends will need to be involved in it from day to day.
Relationships can be difficult and bad things like this happen to people everywhere, but it is important for you to remember that as bad as it seems now and losing someone you thought you could trust, is only bad because of all the negative and sorrowful feelings that a situation like this brings about, you will get past this once the shock of the situation passes. You need to look after yourself, motivate yourself to move forward as that is what you want, when you have moved on and the negativity that clouds your mind reduces you will have realized that situation and learned from it. Give it time but let go of the feelings of sorrow and loss.

NJ