It is always hard to break up but even worse when you have children with someone. Is sounds to me like he is not coming back...he got a job and found a church...and you need closure from him. You need to hear from him it is. The difficult part is that he may not give you that closure. He may think that if he does not then you won't move on and when he wants to come back he can. you need to kich him to the curb. He sounds like you can find someone better....he cant even tell you he is leaving and just doesm, he misses his sons first birthday and knows how much pain he is causing you and does not seem to care much. Is your family around? This will be a tough pregnancy and even harder delivery and yet harder to care for two children under two. you will need to support of someone...either family or friends or even a church...to help you get through this. Don't ever forget that you can get through this and you will because your children need YOU. they truely love you and you should start collecting some child support from him because you may need to money too.
