Brother, trust me when I say this, I know exactly how you feel. I wasn't married but in a relationship with a girl who told me that she loved me more than her life and everything else in her life and though she was engaged to some other guy, she told me that she'd break that engagement and marry me. I tried to ward her off but I was never comfortable in hurting her and so I was in that relationship with her but later I came to know that she didn't break up with her fiance in the first place and has just been using all the while and she did a lot of other things as well that left my reputation shreds in front of my friends and family. Ultimately, I was deeply in love with her and went through hell for 6 months and even after all the drama she's still gonna marry that fiance of her and I'm just repenting to Allah because my Imaan hit rock-bottom in all this turmoil. She doesn't even have any regrets for what she did and rather slanders me in front of our mutual friends.

BUT

Brother, Alhamdulillah, Alhamdulillah, Alhamdulillah Allah's help came and completely changed my condition. Allah blessed me miraculously and today I can say that I'm at least better than what I was and I'm really trying to get that connection with Allah and achieving success in it as well.

Brother, I know that you don't want to end this relationship but you better do it if anything you see in the future makes you suspect her. A third person simply cannot be tolerated in a relationship. Its the worst thing that can happen to anyone and I pray to Allah that he protects all sincere humans from such inhumanity. Make this her last chance because just think that if she doesn't stop all this now then how much more you could get hurt in the future and the pain of love literally takes away a man's manhood (in the psychological and emotional sense). Its an absolute calamity brother to see your beloved in someone else's arms or your beloved desiring someone other than you. It will be difficult but you get rewarded for your difficulties immensely.

If I were in your place, I think I would have ended the relationship by now itself because I couldn't take that pain and I just disconnected myself from her and started working on my deen and Allah blessed with this miraculous change of heart to me.

But also remember that its a test from Allah and you'll get rewarded for it if you show patience but it depends on you whether you take it as a test of your patience and just pure and simple INJUSTICE.

Here's the verse of Surah Araf, v42
"No burden do We place on any soul, but that which it can bear."

Carefully observe the changes and pray to Allah that you are protected from any further betrayal because He's the Controller of the hearts and he might just change your wife's heart towards you with utmost loyalty and respect. InshAllah, I'll make dua for you as well. Careful brother, I don't have to say this because you already know it but still, be careful. I hope you have the best married life. May Allah bless you, guard you and help you in this time of trial.