See Deuteronomy 24.1:
Law of divorce
24 “When a man takes a wife and marries her, and it happens that she [
a]loses his favor because he has found something indecent
orunacceptable about her, and he writes her a certificate of divorce, puts it in her hand and sends her out of his house, 2 and after she leaves his house, she goes and becomes another man’s wife, 3 and if the latter husband [
b]turns against her and writes her a certificate of divorce, puts it in her hand, and sends her out of his house, or if the latter husband dies who took her as his wife...
And in Matthew, Jesus explained:
3 And Pharisees came to Jesus, testing Him and asking, “Is it lawful for a man to divorce his wife for just any reason?” 4 He replied, “Have you never read that He who created them from the beginning made them male and female, 5 and said, ‘For this reason a man shall leave his father and mother and shall be joined inseparably to his wife, and the two shall become one flesh’?6 So they are no longer two, but one flesh. Therefore, what God has joined together, let no one separate.” 7 The Pharisees said to Him, “Why then did Moses command us to give her a certificate of divorce and send her away?” 8 He said to them, “Because your hearts were hard
and stubborn Moses permitted you to divorce your wives; but from the beginning it has not been this way. 9 I say to you, whoever divorces his wife, except for sexual immorality, and marries another woman commits adultery[
a].
I love Jesus, is all to me, and I have divorced when I came to Jesus, cause it was a serious situation. But I want to know you that Jesus KNOW the hearts. Yes, He hates divorce but also love you too much and know what is better in YOUR situation. My husband had another wife, he had two lives, one with our childrens and another with Andrea, his other woman. I DO NOT know that situation, but I did KNOW I HAD TO DIVORCE, and obeyed. So, what I can tell to you? that your situation is between GOD AND YOU, only you too. Only Jesus know your heart, and the heart of your wife, and the future.
Let me say only that I do not consider that the decision about the children to leave with his grandfathers be a wise one. The baby is innocent and need love, and your wife need him. So, I suspect that if you love her, you can love the baby too. And I know your wife need her baby, cause she is mother. I pray you can forgive her and let place to God:
To do His work, His unusual
and incredible work,
And to accomplish His work, His extraordinary work.
Bless you in Jesus Name, and understand your suffering, and your pain.