For me, it's second nature.
But I won't lie. Training used to be difficult.
I remember- that when I was a squire- I only really used one sword for a while.
A rapier- it was. But then, our mentor introduced a new weapon to us, but one we were all familiar with seeing- the shotel. One of the other Squires had passed away from fatigue. I asked if I could pick up the shotel he was to use.
It was difficult at first, and I was- berated for trying to use both shotels, and failing my drills. It's always harder to focus on using both arms in harmony with one another- one thought for two separate weapons, independent of one another.
But- I insisted, that I would become better with time. They admired my dedication. Usually- we practiced with shotel and dagger. But I was the one that practiced with two shotels, as well.
Sure enough, I was soon the top of the class again.
Some people follow suit, but find that they prefer only having one shotel.
Some of the Knights- abandon the shotel all together and return to the safe precise deadliness of the rapier's point.
1.5 imperial gallons of tea were consumed during the writing of this post

"... Fine."