For those wondering why an "ex" makes FL nervous and scared

What's hard in this situation with an ex is that means ML already had a very serious relationship before, not just an ex, an ex-fiance. So that probably went deep and made future plans together.

While this is FL's first relationship, now she'll be confronted with the idea of her boyfriend having to encounter his ex-fiance he was apparently grieving over.

Plus, we don't even know who, how, and why they broke up yet. So, she's in the dark by ML about this.

You'd have to be an iron wall to deny you won't be affected by any of that if you were in the same situation.