Browning lives in Toronto where he is active dad to his 2 kids, who are minors. Alissa works (and lives) in Detroit, since as someone else pointed out, she works at DSC and hangs out with Yuka who definitely lives in Detroit. So it doesn't follow that Czisny and Browning live together. Either Czisny sheltered at Browning's house
before the Canada-U.S. border shut down in March or she has recently found a way to finagle across, on a pretext that she falls within a business/trade exemption to the border shutdown. If so, that speaks volumes about her.
Divorce is expensive. Middle-aged men who start over with younger women are usually able to afford that because they are at the peak of their earning years. Relative to other athletes, skaters (even top flight ones) are not that wealthy, and their opportunities to earn good income declines over time, unless you transition to a new career like becoming a doctor (Joannie Rochette), lawyer (Matt Savoie), investment banker (Sasha Cohen), etc. Or marry money. (Evan Lysacek

).
Browning is popular and in great shape, no question. But he is in his mid-50s and best years for making good money are behind him and declining. He has shown no inclination to pursue school, job, etc. outside skating. A divorce would have cost him $$$ and he still has to support his kids for several years to come.
A woman in her early 30's (like Alissa) may hear the clock ticking and want kids. That's where a 20 year age difference kicks in. If this is a casual or FWB thing, all well and good.But if there is even a hint that Czisny is hunting for a husband or baby-daddy, Browning should run like






, if he has even half a brain.
Second marriages are fine, but starting a second family in your mid to late 50s when you still have to support kids from your first marriage and are basically retired (in terms of career opportunity) is a recipe for financial misery. And if the second marriage doesn't work out, its even worse

I've seen this, firsthand. FWIW.