Why didn't Finland and Sweden ever join NATO?

I think that now they are considering NATO membership.

it had its problems with neutrality in ww2. The other answer about Finland is right. They try to be neutral about Russia, but it just ain't easy.

(that invaded them once before).

It is also an expensive addition to a country's defense budget.

doesn’t count for much.

don't expect America and NATO to come bail them out if Russia attacks. Unlike Ukraine, which begged to be in NATO but was blocked by corrupt Putin-appeasing European leaders - Finland and Sweden have chosen not to be in NATO. Europe as a whole (including existing NATO nations) have to start contributing more to their own defense. The reason they have so much better healthcare than we do is because our taxes have to fund a large military - that they expect will protect them should Russia attack. F that - let them start stepping up and contributing more to their own defense and to collective Western security.

... dating back to the treaty they signed with the Soviets in 1948. Despite two armed conflicts with Russia between 1939 and 1941, the Finns managed to hang on to their autonomy, albeit with some restrictions, like a limitation on the size of their armed forces. This is more than can be said for most of Eastern Europe.

The Finnish attitude has been described as "bowing to the East without mooning the West." After the breakup of the Soviet Union, the Finns stayed on essentially the same path, but I think they are now reconsidering.

The Napoleonic Wars was the last time. We have sent peacekeeping troops multiple times.