He left you for her. She is expecting his baby and he's calling you, cheating in at least an emotional way.
Is this the kind of man you want? Taking no responsibility for his actions, not even caring about his own baby except that he wants it "out". Pfffffttttt....you can do way better than this, and deserve better.
When the fantasy of what might have been is filling your mind, take a good look at "what is" and move on. Good men don't behave like that, and there are lots of good men out there.
More important than any man is finding yourself, discovering your own dreams and happiness that don't depend on anyone to achieve. YOU hold the key to your happiness and don't need another person to help you unlock the door.
Hugs