Open letter to my mother

So, recently I got a message from someone I haven't spoken to in a long time. This person is not my Ex but my friend's Ex, so I wondered why is he contacting me? This got me thinking should we still be friends with our Ex?
Some find it hard to let go. Some people log in through a mutual friend's profile, just so that they can keep tabs on their ex, without them knowing. Letting go can be difficult. Letting go of people, ideas, expectations, desires; letting go of bad habits, false beliefs and unhealthy relationships... the list goes on.
If you want to move on, you must leave the past where it is: in the past. I'm not convinced you can have a new healthy relationship if you are still in constant contacts with your ex.
Every day, every moment presents an opportunity to create ourselves anew, to shrug off the baggage of the past, open ourselves up to the possibility of the moment and take action to create an incredible future.
Some believe you don't have to burn all bridges with your past; they say it's possible to have a healthy platonic, no-strings attached relationship with their exes. Some of them even say they are best of friends now. One woman even said she is such good friends with her ex that she approached him to help find a job for her current husband - by the way she still hasn't mentioned to her husband how his new job came about.
So I'm asking an open question:
Is it OK to get in touch or stay in touch with an Ex?
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That’s a very technical question but for me i will say its good to stay in touch. so they won’t say you left them totally because you guyz broke up.
Personally i don’t agree with boyfreind or girlfreind, for me I’m a male youth and the only woman i want to share a relationship with is the wife God leads me to, till then i abstain from any form of girlfreind/boyfreind matters as it causes temptation for me.
Attraction is a funny thing. Sometimes it just never dies. You may attend a 30-year high school reunion, see an old boyfriend, and have the same giddy feeling you did as a 16-year old. This nature of attraction must always be kept in mind and respected.