I [29M] found her [28F] texting her fwb. Is this cheating?

Been in a relationship for about 5 months now and I '29 M' just found out that she's '28 F' been texting this dude that she used to hook up with as early as 8 months ago (so 3 months before we got into a relationship) The texts are flirtatious (the recent ones) but no sexts from what i can see (there was alot of sexting in the older texts) I did see that she turned down his most recent hook-up offer (which came around the time we started becoming serious). She didn't really tell him that she's getting serious with someone but brushed it off like she was just taking some time off and being a "good girl".

I wanna know would you still consider this cheating?

The fact that she is still in contact with him feels a bit wrong to me and the flirting feels like crossing a line. But I do trust her and don't think she will sleep with him again.

She only wants her close friends to know that she is in a relationship so she keeps me away from her social media (her socials make her look single)

We have had a conversation about it and i don't mind her doing this as her reasoning was that she doesn't wanna have to do a bunch of cleanup if things didn't work out.

What should i do? Should i confront her?