Hi, I'd like to help you with your question.
It depends on your son's age. If he is under legal age (18), your husband's actions will affect how he views marriage and commitment. He will see that his father is not committed to the family and to you. Your son may struggle as an adult being faithful to his wife and family. Or he may decide he wants to be committed no matter what. It depends very much on how he sees the situation and his personality.
If your son is 18 years or older, your husband's behavior is still not a good influence, especially if he has been behaving like this throughout your son's life. But if your husband just started this behavior but was faithful before, your son will probably feel betrayed but he also has an adults understanding of the situation.
If your son is young, you may want to consider counseling for you and for him. This will help him see that his father's behavior is wrong and hurtful. Your husband is also being self centered and taking advantage of everyone in the situation and your son needs to know that this is not typical behavior for a husband and father. Hopefully, if you are taking legal action against him, he will be stopped from continuing his destructive behavior and your son will not need to be exposed to his behavior anymore.
As for your legal questions, you may want to try asking an Expert in Just Answer's legal category. I am sure someone there could help you find answers.
I hope this has helped you,