Err shadow is asking a valid question, one that came to my mind too.
How did you end up looking at his search history? Do you check this often? Does he know that you check this often?
My abusive ex did this exact thing. It is a thing.
Now OPs anger could just be a thin veil over her fear.
Or
It could be a result of years of abuse.
Having been suicidal, it doesn't take 8 months to decide how. And that Google search would have been one of the first ones, not after 8 months.
Something in his story doesn't add up. But good re samaritans. Next is 111. Get him in a psych hospital, its the only place that can keep him safe if he is genuinely suicidal.
Incidentally, with my ex, the hospital psychiatrist told me that he was a higher suicide risk than my ex, it was manipulation.
Only OP knows the circumstances.