How can I be excited for my SO? What would you do?

My SO and I have been talking going on 1year and 5moths now. He has a baby girl him and his child mother wasn't together at the time we stated talking and I knew all of this when we first meet. Time progressed on and we were seeing each other more and more feelings started getting involved, emotions came about for one anther he then informed me that he had gotten back with his back with his child mother. Yes I was heartbroken and hurt... We stop seeing each other for maybe 2 weeks and we picked things up right where we left off.  As time is still progressing so are out feelings toward one another, his child mother breaks it off with him, but things are still the same with us.... With all this happening a year has went by we celebrated and feelings are more involved. At times it feels as if we are in a relationship without the title "boyfriend and girlfriend"  yes we do love each other and he tells me all the time he wishes things could be different.... We both love each other and would do anything for one another. He then later tells me that his child mother is pregnant with baby number 2, my heart was sooo empty, I felt soo alone, all I could do was cry. So now were at the point were it's like how do I be happy(incorrect grammar) for him and try not to hurt or have hurtful thoughts at the same time.... Him and his child mother still aren't together... Honestly I don't want to lose him and I want the best for him. Some time I really want to tell him just to go ahead and be with your family I'll be okay. But deep down inside I won't be. How do I handle this???
*the entire time we've been talking he has been taking care of his child like a father should be*