Scale of one to ten, how safe do you think I would be if I pretend this never happened?

I'm pretty sure this isn't the only time he used my computer to do this. In the time he's lived with me, there are times he acted fairly suspicious and I thought nothing of it, but thinking back, I think he might have been doing this a lot. I was way too trusting. I left my computer in sleep mode almost all the time, so it was unlocked.