It sounds as if he’d been seeing her and planning his ‘exit’ from your relationship for longer than you’d perhaps realised. What might seem like a whirlwind for you therefore (and probably you’re still in shock/feeling a bit lost), was a cold, calculated plan by him. He has gone into the arms of someone. You’re alone. But honey, it’s better to be ‘alone’ than live with a cheating, lying toad. You’re now independent, free and have more options and freedom than you’ve had in years…It can take time to embrace singledom; especially if you were together for a long time. But with friends and family around you, a good counsellor and a Fk-him attitude, you WILL heal. Be kind to your soul, your mind, and your body on the healing journey. Eat well, try to get some quality sleep, and if that cheating ******* finds that his online romance becomes a fantasy that doesn’t work out in real life (the day to day reality of chores, jobs, bills etc), think about whether you’ll take him back if he runs back to you. (I hope you shouted out ‘Hell No’ to this!)

Once a cheater, generally, always a cheater.
Sending you virtual hugs and good vibes for a happier life 🌸