Oh dear OP! My heart goes out to you. I never follow up with threads, but for some reason have with yours... I just get the feeling of 'want to save you' after reading the developments! Warning! Long post!
I am so sorry to have to say what I am about to say (and I sincerely pray to God I am so terribly wrong on this one!)... [I will refrain from swearing because I don't want that to hurt your feelings or deter from the seriousness of my comment].
It STRONGLY SEEMS you have married a condescending, chauvinistic casanova i.e a man who has no regard or respect for women. Someone who sees women as a commodity for his own pleasure and use -_- I'm sorry!
Considering your age difference (not that age matters) in the sense of maturity... your husband straight up sounds like someone many sound minded independent and secure women would stay well away from!
As others have commented and I think you have also insinuated... had it not been for lockdown, you two probably wouldn't have been together. So it's not that your marriage was rushed, it's that you didn't actually form a bond and test your relationship it seems in the actual reality of life. He hit jackpot by scoring you as someone to warm his bed full time [marriage].
I'm sorry honey, but this man does not seem to have 'changed'. A changed man would not be talking so boyishly about a lost flame he couldn't resist! The details of what he has shared with you, blatantly screams where this man-child is at - charming the pants off women [quite literally] with ZERO heart for the damage he is causing! He sounds like your typical charmer [probably good looking too], going about letting his dick lead the way! In no way marriage material!
I doubt he even has any real value for marriage! He's 40! Not really stud muffin age! When a charmer does not embrace age, his level of appeal to secure women, drops lower than his balls! Nothing more cringe than older people trying to act like reckless 20 year olds!
I'm sorry OP, your questions you have asked in which you are clearly hoping someone say what you want to hear [that you've nothing to worry about and that he's a good husband], show, you know in your gut who you have married? You probably have that 'I can't trust him bottom-line', feeling in the pit of your gut?!
Girl! Only you know this man and why you married him. Were/are you secure in yourself? Were/are you happy as a person on your own? [And I don't mean happy being single, I mean, content with most of yourself] were/are you independent? Do/did you have loving family and friends around you? If you have answered no to any of those... I think you know how this marriage came about - you 'needed' him and settled for far less respect than you deserve?
This woman aside, there's a bigger underlying insecurity here it seems. You can't trust him in your gut around any remotely attractive woman. He has created that insecurity [happily it seems]. This woman appearing has just brought those pushed down feelings to the surface?
No one gets married to get divorced. I would not say you divorce him. That's not my place to say.
BUT as others have advised, protect your life and become self sufficient as you would being a single person, for at least a year to see if he trips, and in that year, see how he is around women in general. A player is usually overinflated in their own mind. They're usually not at all appealing to real humans! They prey on girls/women who are simply vulnerable, insecure and troubled.
Nonetheless, he in all his glory as he appears to be to many of us in this thread... will not be able to resist temptation, and when he goes there... YOU NEED TO GO OUT! I pray I am so terribly wrong! But in no circumstances should anyone be with a cheater! And for anyone who defends that; they are just lying to themselves.