Yours, Mine & Ours (2005) on Netflix

High school sweethearts Frank Beardsley and Helen North nee White are reunited when Frank and his family move back to his home town of New London. They are instantly attracted to each other and quickly decide to marry. They are quite cognizant of the fact that he already has eight children from his first marriage, and she has ten from her first marriage, hers a mixture of her biological offspring and a rainbow of adopted children. What may be more problematic is that he is an Admiral with the Coast Guard and as such has a very regimented view of how things should be done, whereas she is a free spirit - she is a designer by trade - with a more lackadaisical attitude. Their respective children, who are a product of their parents' views, hate each other. They however feel that they can better rid themselves of their new situation by joining forces to show their parents their respective philosophical differences about life. Regardless of if they achieve their goal, the kids' plan may also have some unexpected consequences.