U have to find out is it her fault or her bf from 3rd party point of view.

Like some pointed out, she can be opportunistic, but she might also deserve 2nd chance if her bf was really shit.

The question is would you be able to find out and get a convincing answer as to why she have no interest with him anymore?

I would prefer a more honest explanation that put herself a part to be blamed that cause the relationship turned sour.
If she say it is all the boy fault and her only mistake is choosing him, then she is very self entitled.

Well we can't be judge for you, this require you to analyze yourself, we can only give guide. If you feel any ambiguity with her explanation not willing to be more transparent with you, that unknown can be dangerous for you to commit in to the relationship.

In the end of the day no right or wrong, it also depends on what u seek in a relationships, she said he wasn't a husband material, but do you see herself a waifu material as well? Or just an opportunistic?