Yes, I believe so. Many people, today, if they find a great sex partner, especially if the man is overly endowed, length wise and thickness, and his significant other can take all of him, doing everything in bed he desires, and giving him sex as needed -- yes, they will remain together, probably. There is no statistical data on this.
Now, when the significant other refuses or no longer wants sex...then, the man may seek over avenues for his pleasure.
Since AIDS is still out there and there is no cure, many people stay together because at least they know the person they are with is clean, and they do not want to take a chance.
I know married men are paranoid about that; they do not want to bring anything back to their wives. So, if they find/discover a good, fuck partner (a long-term sexual commitment), it is all good.