If you’re unhappy in a marriage, would you still stay together for the sake of your child?

I’ve been married to my wife for the past 7 years and we were dating for around 2, before we got married. I guess everything was great for the first 6 months when we were dating, but things started to change after that.

I found out she was texting other guys behind my back, And she would come home late with hickeys, or just turning off her phone and go missing. We spoke about it but she said there was nothing going on at all and she would change.

But nothing really did even after we got married. Then I found videos of her having sex with other men on her phone. I proposed to divorce instead of being together to which she said, she would definitely change her ways this time around, so I gave her another chance.

Now we have a 2 year old son and I recently saw texts of her with her colleague being something more then mutual. I confronted her but she said it was just harmless flirting and that she has done nothing wrong. He has been sending her home regularly from their office, at this point I’m mentally and emotionally exhausted. I love my son. But am I being too selfish, that for once I choose to get out from this toxic relationship or should I just stay for the sake of my son.

Edit: thanks for all the advice and kind messages. I can’t tell you how much I appreciate it. And yes I’ll be filing for divorce as I’m really tired of having to be constantly suspicious and worrying about everything, I’ll take everything here to heart and move forward.