Is it permissible for a divorced woman to return to her husband who has remarried and had children, which might cause problems with his new wife?

If the wife separates from her husband without a divorce, and the husband asks her to return, she must do so; otherwise, she is considered disobedient (nashiz) and is not entitled to maintenance or housing. However, if a divorce occurs and the waiting period ('iddah) ends, she can return to him with a new contract, unless she intends to harm him or her co-wife.