How to make my sagittarius man back? HELP?

Sorry, as blunt as saggs are he has made up his mind and he has moved on. Only thing I can say is to let him go and go about your life and hope he comes back since saggs usually do after awhile. He sounds like he needs his freedom but deep down he will always love you. They always do. I dated a sagg and every now and then he will say hi but we dont get back together, Try a gemini :D

There is nothing you can do if he is ready to move on. Wise not to hound him, as that will only push him away more. Speak your truth, and then let it be. Sadly this is not much of an astrology question, as there are no charts.
If he returns - great maybe you can both learn to love each other in a better way. If he doesn't return, this hurt too will past, and learn from this journey, and not bring it into the next relationship.
We cannot control people, and when we guilt them back, sadly, it does not work out well. I deal with thousands of clients, and have seen this happen many times.
Good luck.