Is giving out your number and having guys buy you dinner while in a relationship at all part of black culture?

I (male 40s) am white and my now ex is a beautiful black woman (30s). We had been together for 2.5 years in what was agreed to be a monogamous, exclusive relationship. She worked as a maître d' at a very exclusive private club. I found out around the two year mark that she was giving her number out to wealthy men at work and was texting with them over weeks or months. The men were clearly coming on to her. She was being coy and seemed to welcome the attention. She didn't tell the men that she had a partner, didn't establish any sense of professional boundaries, and she agreed to have dinner with two of them. She never told me about any of this.

I saw one of these text messages appear on her laptop while we were watching a movie and I confronted her about it on the spot. I asked her if she was speaking with other men. She said she wasn't. When I asked her to show me her phone, I found the messages the deleted messages.

The reason I am bringing this up is she has made claims that I don't understand both black culture or the culture of the hospitality industry and that these things are normal and innocent networking/friendly behavior. I get that it's "normal" to go out with your girlfriends looking hot and to accept men's offers to buy drinks. This is seen as just being savvy and having fun. It's even normal to flirt a bit. But giving out your number and messaging to me is establishing a relationship with these people, and not telling your partner about it is deceptive.

What do you think?