There is no legal and official means of checking him until you both decide to get married. Then he must submit legal documents stating he is divorced or married or whatever.
Another concern is that, he told me that he had a chaotic life in the past. He was illoyal to his wife for many times and kept several women at the same time while he was married. Karen
Oops, he is really a womanizer.
Polish men are no better or worse than men in other parts of the world. They are the same - some are faithful, some are not. Even religion has no influence on it.
If you treat your relationship seriously, talk to him. Ask him about his plans.
Being so much concerned about his marital status, you probably think of marrying him. Why don`t you tell him that?
Men don`t like such confrontations but it is the only way for a woman to know something.