Hello Adriana and welcome:
Gee, that must be heart breaking, after 5 years of trying to make the relationship work and looking forward to your wedding and all.

So sorry for that hurt, Adriana. These are losses that you will probably need grieve thoroughly. No wonder you are reeling and feeling so sad.
The good news is.....you didn't marry this jerk who is playing you like a yo-yo. One minute he's going to marry you, the next minute, he's gone. Seems he's repeating his irresponsible/cruel/twisted behaviour of the past.
He has three children he doesn't talk to? Nice dad.

Be glad you didn't make any babies with him!! You and your future children deserve much better than this!!!
It's so sad that they never change.
This is the hardest part for me to accept. It is very sad too but so far, it's true (in my situation). I don't think this jerk is going to grow up or change into some nice guy/father/partner magically, if ever. First....he would have to acknowledge that he has a problem and then seek help with it. Doesn't seem likely does it?
I'm sorry that it hurts for you right now, Adriana and I know that doesn't help much but I just want you to know that you are not alone in your pain. It will pass and you will go on with your life. You deserve to be with someone who will honour you, not treat you like dust. No matter how tempting it is to listen to his bs......don't do it!!! He's going to try to lure you back......don't bite.
You don't need to live your life with someone who has so little respect for you (and evidences his disrespect for others so clearly). Don't settle for so little. You can do much better!!!!
GFN