Dating a married Jewish man

Hello there, I am dating a Jewish man, who was previously married to a Jewish lady. However, they separated many years ago. But the divorce was not processed. He is in fear of divorce and then remarriage. His fear is that if he does divorce and remarrys, this would make his ex become an adulterous if she remarries in the future. Is this correct? For context, I am personally not Jewish myself. I am Christian.

Shalom,

He is absolutely right.

Until he divorces his wife, she is considered married and cannot remarry another person. Remarrying without a get  is one of the most severe biblical prohibitions.

Additionally, torah prohibits intermarriage between Jews and Non-Jews.

Vayikra  20:10: ' If a man commits adultery with a married woman – committing adultery with another man’s wife – the adulterer and the adulteress shall be put to death'.