My partner is a very girthy 9 inches. I had a bit of trouble initially because my "second hole" wasn't able to take that much girth.
At the start of our relationship, we were fucking every day, sometimes more.
I had to slowly stretch it with a flexible dildo before sex as part of my douching routine. I had heard about guys getting a perforated bowel from aggressive sex so I wanted to reduce the risk.
It's a problem that resolves in time, the more practice you put into it. It's just that if you want to get to taking it like a pro, you need to spend the time on your own than trying to go through the awkward phase on game day.