Shon Hyneman:
American author and adiseur social media marketing.

No matter how many losing seasons you might have had in the past with your marriage, the good thing is that all teams get a fresh start once September begins.

It’s built on an extended football metaphor for marriage.
“Losing seasons”
= the rough patches, conflicts, or difficult years a couple has been through. “September”
= football season kickoff in the U.S. (NFL/college football traditionally starts in September), which the author uses as a stand-in for any new beginning.
The point is optimistic:
however bad the “record” of your marriage has been — however many fights, disappointments, or bad years — a fresh start is always available. You’re not locked into your past performance; a new “season” wipes the slate clean if you choose to treat it that way.
Origin:
It comes from Hyneman’s book itself, which uses football/sports analogies throughout (playbooks, teams, coaching) to talk about marriage and relationships — the quote you found alongside it about “reading your Playbook” (the Bible) if you want to be “in sync” with a spouse is from the same book and same football-as-marriage conceit.
Author: Shon Hyneman
– author of “Love and Football”.
He’s a relationship/marriage author who leans on sports metaphors as a hook, likely aimed partly at football fans or men who respond to that kind of framing. I don’t have independent biographical detail on him beyond his authorship of this book.