Since C++17 you can use range-based for loops together with structured bindings for iterating over your map. This improves readability, as you reduce the amount of needed first and second members in your code:
std::map<std::string, std::pair<std::string, std::string>> myMap;
myMap["x"] = { "a", "b" };
myMap["y"] = { "c", "d" };
for (const auto &[k, v] : myMap)
std::cout << "m[" << k << "] = (" << v.first << ", " << v.second << ") " << std::endl;
Output:
m[x] = (a, b)
m[y] = (c, d)