Well not necessarily! I have remained friends with some former girlfriends and now even with those men whom they later married. My wife has made friends with them too. May I help you as i teach russian speakers in Oxford and on skype, Anastasiya?  I am of course a native English speaker. If so do please send me a message here. 

continued ....

It might not be directly link with your question, but I want to highlight how my inaction on knowing something was wrong was causing damage to both our lives, and even though I pointed it out and asked her to change it with my help, it wasn’t happening. The only thing I could do was force the change, and leave, and it worked out. Sometimes not everyone is strong enough to help themselves and you have to help them, but by worrying about your decision over this person you are already damaging your own life in some way, and I am sure it is affecting you own dreams and ambitions, and having an effect on the enjoyment you take from life. We have to be selfish, we only have one life and we owe it to ourselves to be happy.

I was in a relationship for 5 years, 3 of them out of convenience. I realised although I still wanted to be with the person, she wasn’t the one for me, and it was damaging her life. I had become her everything. She had no friends, no ambition to move out of her parents house, no need to find a decent job, because I provided everything for her. She hung out with my friends, I earned good money and could treat us both. I realised I had to leave her to shock her to the core, and get her to kick start her life. I also had to do it for myself, because all my dreams and ambition had went away. Here I was in a relationship out of convenience, that benefited no one, and caused destruction to everything we had wanted, and I couldn’t do what was needed because I didn’t want to see her hurt, but I soon realised I’m doing more damage by being with her and letting her stay in these habits. No matter how much I tried to push her to find her passion again for all things life it was gone, and breaking up with her was the only thing that could change it, so I did. It hurt like hell, I thought I had made the wrong choice, and I regretted everyday for months. But then my life picked up, I moved and got a better job, I made new friends, I started visiting places and doing things I had always wanted to. Then I heard from her a year later and she is doing really well. She now frequently goes to events with friends and is allot more social and confident. She now has a much better job, and is pursuing the career she wants, and has also bought a house.

Let's examine the sentence.

"Sometimes it's necessary to abandon a person "forever", let him go out of your life in order to enable him to make an important life choice. And, there's no any guarantee he'll be still with you"

First you have "Sometimes".  Sometimes is a nice way to get you ass covered so that the statement is true in some cases but in other is not.  Basicaly you can never go wrong with that.  Let proceed with what the statement is saying.

" it's necessary to abandon a person "forever", let him go out of your life in order to enable him to make an important life choice"

It is saying "abandon a person to enable him to make an important life choice".

Notice the word "him" .  So although you say it is about anyone the statement clearly states that the person is a guy.  I will assume though that the phrase it is talking about anyone.

I proceed.

So again it says abandon in order to enable.  Hmmm.

The question is why the non abandon is a disable ?  Is the non abandon a disable ? If so what kind of relationship (of any kind) is that were the non abandon is a disable.  Clrearly not a beneficial one for the non enabled person.  So we need to ask the question, what exactly is the person doing to disable another person from making a decision ?  The answer needs to be clear if we are honests.

It should be stated as "My presence disables you from making an important decision because X".

If not so we have to examine if it is not just an excuse so that a person abandons another person for a number of other reasons and not to truly "enable" them or set them free.

Elmo and Jonathan that's great to hear your personal opinions. Thanks for participation.

Guys, while reading all your opinions, I'm more and more convinced this issue has a huge number of definitions for each of us. It's naturally everyone perceives it in his own way. The main reason here why I've decided to put forward the topic for discussion was to know what other people think about it. The statement, as it seems at the first sight, is quite simple to be answered but a few minutes later we can realize it's not so.
As I said above, I'm interested in such kind of issues. It gives an opportunity to reflect. That's amazing, isn't it?

Although, I'm inclined to believe, at some moments when a person tries to make a very important life decision and looks "lost", we must give him a time to understand himself. In my opinion, it's necessary to avoid future problems connected with a tipical word-list as "you allowed me to make the wrong decision", "you have compelled me to make the wrong choice" or "you've been wrong" and etc. It sounds quite selfish but nevertheless lots of people are afraid to hear such words.