how do i talk about it?

(please let me know if i need to add a trigger warning).

this is gonna be very wordy because i over-explain things and feel the need to clarify a lot, sorry.

i'm not ready to open up about my eating issues with anyone else, so i'm not looking for advice on that.

i've only told one person about my disordered eating habits and its results even though i kept it secret from them as well for the first 2 1/2 months it'd been going on for. they've known since then now, but i rarely ever tell them the moments where i'm struggling, especially purging.

i've always had the habit of not replying for quite some time and it's become expected of me to reply late (but my friends thankfully don't mind). but i don't know if i should be honest and tell this person i was purging for over an hour, haven't eaten anything, etc, or just not mention it at all. honesty is important in close relationships like this one and i trust this person with my life, but i worry more about scaring them than i care about getting things off my chest and being honest about what i'm doing and how i'm feeling. i mean, i've even told them i have no clue how to talk about my eating issues and they told me it was okay and i don't have to if i don't want to. i've always been the type to prioritize myself last, especially in recent months.

i know eating disorders/disordered eating thrive in secrecy and make the sufferer feel alone and isolated, especially if nobody they know can relate to their experience. and both of those apply to my case, as far as i know, and bottling it up just makes me feel worse.

should i be honest? should i tell them when i'm having urges? or do i just keep hiding almost everything from them so i don't make them worry too much?
i just don't know what to do, and i don't know how open other people with ed's/disordered eating are with close friends about their behaviors or what's "appropriate" to share, etc.