Sorry to hear about the tough situation with your boyfriend, @briggitte. I understand this must be tough for both you and your son.
Like Francisco mentioned, definitely think on it for a while before using your magick to influence your boyfriend’s decisions. There are many bumps in the road of life, and sometimes things that seem very bad can actually lead you to a better place, somewhere that you may actually be happier- even if it can be hard to imagine now.
If you do decide to work magick of some kind (whether to try to bring him back, or to strengthen yourself and self-love), definitely cleanse the area beforehand. You will want to banish any negative or dark energies that may cloud both your mind and your spellwork. @SilverBear has shared a great (and also quick and easy!) Salt Bowl Cleansing Ritual 
I would also recommend doing some meditation beforehand, to help you approach this issue with a calm and sharp mind. If you’re interested in trying meditation, I’ve found Breath Meditation, Meditation Tips, and @MeganB’s Meditation Guide to be very helpful! 
I hope that this situation resolves for you, and that you may find peace and happiness! Sending lots of good energies and support! 