I believe in honesty first. I have seen how lies can literally ruin people's lives. I also believe that of you're not upfront, how can anyone help?

Like LT said, there is a range of ways your T can react. I need my Ts to not panic and definitely not threaten hospitalization. Then again, I'm not currently SH'ing and haven't for 8+ years. L and I process why my SI and SH parts are active: what they need and want, what they're trying to say or what they're trying to protect me from. We find value in all my parts including the dangerous ones.

It's completely up to you if and how you disclose your SH. You can always have a discussion about your history with SH and what type of reaction would be helpful BEFORE you disclose the current SH. That way you can get a feel about how she'll react.

If you want help with it, I firmly believe being honest about it. Again, that's just me.