I am guessing your father grew up in an era "when men were men", "spare the rod spoil the child" and "men don't cry" era.
That's so true. I've often wondered why I grew up to be a pushover, as my kids all tell me I am. It was hard on my wife but our kids loved it until they had kids of their own and now they don't like it.
Your photo of your mother and dad reminds me of what a promotional photo of two movie stars of that era looks like.
Now that you say that and I look at their photos again I see it!