I tend to agree with Ringtail. I have a good body of experience in sigil magic targeting the external, many times people directly. While the ethics of those practices might be questioned, and the results a bit unpredictable (all magic has potential for unknown ramifications), I've found servitors to be more effective in both single-target and area of effect workings. Should you push forth, magickally speaking, I suggest that route.
All that said, it's probably best to have the tough conversation. Especially if your partner is emotionally unstable- we don't want that to become exacerbated by any magickal random weirdness.