If there's antifreeze in the oil the oil would look milky white. If there's oil in the antifreeze the coolant in the radiator will have black or milky looking splotches floating in it. They can mix if the head gasket or timing cover gasket ruptures or if the engine develops a crack. Pull your dipstick and look at the oil on it. Then remove the radiator cap and look at the coolant. Best to do it when before starting so the engine is cold..
Broken seals cause this.
Soon your car will blow out smoke. Very expensive job!