After the Norman Conquest of 1066, English kings had roots in, and territory in France: Henry II and his queen Eleanor of Acquitane held more of France between them than the French king, and spoke French. So England was always necessarily involved in French politics and struggles, taking sides when there was a war of succession in Brittany, or a revolt in Flanders, or defending its claims to French territory in the Hundred Years War. Not until the mid 16th c., when Mary I lost Calais ( in a bid to help her husband Phillip II) could you say that England had no territorial claims there.

After the territorial claims were mostly gone, they were still involved politically. The English queen and royal court fled to France ( her country) during the English Civil War, Charles II of England was regularly paid by Louis XIV of France. French aristocrats fled to England to escape the Terror in the French Revolution, Huguenots earlier, to escape religious persecution. They had adjoining and conflicting colonies in the Caribbean and America. However, although England would continue to have disputes with France through the 17th and 18th centuries, until Napolean, it's not correct to say they exclusively fought each other. As well as internal civil wars, France and England also got into wars with many others- Spain, the Dutch, Scotland...there was an English army wandering around in Germany in the 30 Years War, and a long period of French involvement in Italian Wars in the late 15th early 16th c.