I ask Allah to relieve you of the pain of your conciseness and to provide you with a sincere repentance. It was and is still easy for both of you to engage in a clean and pure life under the shade of Allah, since Allah allowed a Muslim man to get married to more than a wife. Committing suicide is not a solution for your problem, but it complicates it, because you would be held responsible before Allah for the child you have killed and for your own self. My suggestion for you is as follows:

You must stand before Allah in a true situation of repentance regardless of how much you loved this man and how much you love your son to live in a family. Just admit your sin before Allah and have a resolute that you will never do it again.

In addition, strengthen you faith by increasing prayers, fasting, and giving charity. Insist on Allah and Allah never closes His gates in front of His sincere repentant slaves.  He says in the Quran, “Say, “O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful. And return [in repentance] to your Lord and submit to Him before the punishment comes upon you; then you will not be helped.” (Az-Zumar 39:54-55)

In case the man prefers his fame and showing off in front of people instead of pleasing Allah, make sure that he is not a good Muslim and he will not take full responsibility. He just uses and abuses you. Do not shed tears on people who do not deserve. Regard your son as an orphan and you are spending and caring on an orphan seeking the pleasure of Allah. I do not think it is permissible for his biological father to attribute him by giving him his name.

3. Leave the place where you can see this man. The one who killed 100 persons and upon asking a scholar what to do, he advised him to leave the place of sin where he used to stay. Clean up your surroundings of all factors that may drag you back to sin and Allah will defiantly provide you with a better husband where you can better improve your faith and draw closer to Allah.