Welcome to the forum.
I agree with Karen on all points.
I also have the feeling you are quite young. Learn from this experience, be responsible for you, use birth control, do not let your BF or anyone convince you otherwise.
I would suggest focusing on you and your boyfriend when you communicate. once and awhile ask how is other child is. Show interest, but to do keep throwing this in his face. REMEMBER, he has NO control over how is family responds or acts toward you.
I have posted a link for you. PLEASE read the 21 points that are listed, some may be very helpful for you. www.lifehack.org/articles/communication/21-best-tips-making-long-distance-relationship-work.html
You are not alone, we are here for you, keep posting we will listen and support the best we can. However, you must do the work.
Peace and strength