I don't think it's particularly helpful portraying bee63's son as selfish or the villain. Once he was an innocent CHILD who had no choice but to be raised in an abusive home, where at the very least, he was witnessing abuse (this is considered a form of child abuse), and probably felt terrorised by his father.
Being directly abused or witnessing abuse can be incredibly traumatic and damaging, and something that many adults, let alone children, struggle to deal with. Some never come to terms with it. Abuse is something that should never be minimised, and I'm appalled by the fact that some people think that it's something that victims of child abuse should just get over and stop moaning about. Maybe we should start telling victims of spousal abuse to do the same.
Bee63 has stated that she felt that she wasn't a particularly good mother, that her son had an awful childhood, and that there was ABUSE. So clearly, her son has every right to be angry.
Bee63, you were clearly in a terrible situation, but your son is probably angry with you for raising him in an abusive home, and not protecting him from the abuse. And as I've mentioned already, simply witnessing abuse is abuse. There is no such thing as a child being raised in an abusive home and not being negatively affected, often badly affected by it.
There is a chance that he doesn't want anything to do with other family members because they were enablers or continue to enable, e.g. covered things up; turned a blind eye; made excuses; minimised the abuse and told him to 'get over it'; called him a liar; were angry when he wanted to talk about certain things; didn't believe him when he asked for help; accused him of being a troublemaker, selfish or unforgiving etc. when he spoke out or refused to put up with bad or abusive behaviour. In an abusive situation, individual children can also be singled out for abuse, or can be expected to take care of the family, and are often blamed for the behaviour of the abusive parent, or expected to take care of the abused parent. This can be an impossible burden for a child to carry.
Bee63, you've stated that 'I haven't explained everything about my relationship with his father.' Your son has probably picked up on this and doesn't trust you as a result. If you do ever get a chance to speak with your son, then maybe honesty is the best policy. You may not get the result you want but at least you tried.
This is obviously a very complicated situation, but people blaming your son isn't going to help, and will only make matters worse. It is an attitude that will drive your son away. Also, I think it's important to remember that on the one hand, bee63, you are a victim of abuse, but on the other, your son is also a victim, and that mustn't be ignored.