This based on my experience with my ex.

My ex had quite a number of male friends from uni, workplace. At the end of the relationship, I dumped her after noticing her behaviour changes, she would hide her text messages and ask for space and more personal time.

Final comfirmation come to me when one day I noticed her sexy romantic chats with one of her so called male friends.

Yup, women will always find better version of men while still being in relationship or married.

This behaviour is already hard coded into women.

Yes will leave as I sense it as a red flag.

If she spending time daily up to 4 hours with her male friends, in my opinion her relationship priority has gone else where and you entered her 50 50 zone.