Itaz,
let me get the facts straight.
1. A boyfriend/former boyfriend (who you say is a nice guy) got you pregnant.
2. You are now six months pregnant, living with a guy who got a girl 5 months pregnant.
3. You have a crush on this guy but you have mixed signals whether he wants a relationship with you. His ex-girlfriend who is going to have his baby does not want you to get attached to him because if he gets attached to your baby and you leave he will be heart broken. (is she still in love with him and may want him back?) he is sending the father of your baby text messages that you want nothing to do with your former boyfriend (is he jealous of your ex, because your ex is going to father your baby?).
What a love rectangle!
First of all, you need to get over your crush and live in the real world. You are going to have a baby! He is going to have a baby! And your baby is not his baby!
Before both of you can even consider having a relationship, you both must determine if you past relationships are finished. It doesn't sound like they are or there is no closure. You need to not look out what is best for you both but for your babies.
First, love is never confining but wants what is best for the other person. You may need to have a heart to heart with him on what is going on in both your lives. You both need to communicate and honest with one another and sort out your feelings. Find out if he loves his ex, find out what he thinks about his baby. I give him cudos for watching after you, but is this guilt because the mother of his baby is not allowing him to do this for her. Before you both open the door of a relationship with one another, you must close the door with the ex's. This could be difficult because either you might make it work and the other it might not make it work which could leave one of you alone?
I would not go beyond friendship before you both close the door on your prior relationships. Especially since these ex's will be in your life constantly because of the babies you all are having. You want the spark of your former relationships extinguished so the flame doesn't arise when you are in a committed relationship.
Also, wait until the babies are born before doing this. May be the birth of these babies will change the way you and he feel about the babies birth parent.
All I am really saying is you need to look at the situation, and determine what is best for you and your baby. You are in a tricky situation and would take it slow so the direction you move toward will be permanent and happy.
Best wishes and congratulations! I do wish you well!
Tomz