LDS ONLY: Why can you be such a nice giving good person and not go to heaven if you don't accept lds religion?

I just don't understand. I try to be a really good person and don't sin and keep the commandments and I am not going to heaven for not accepting to make covenants or not accepting the church. Also I know there are 5 heavens and I don't think the telestial kingdom is going to be happy when I have no family at all. As they say you can't be with your husband or see your children unless of course I have girls and I don't and they don't go to heaven.