There’s suspicious activity on my SO’s computer that their blaming me for that I didn’t do and idk what to do.

The other day I tried to get into my SO’s computer to access an account I needed to fix(not a problem I use it all the time). Before I could do anything the computer malfuctionedned and died. I tried to get it back and running even working with their roommate and texting them for help (they were not home) to fix it but was ultimately unsuccessful. Eventually, we got it working but not in time for me to use and I had to go home. Later that night, SO found activity on their computer that neither of us did but it coincides more with something I would do. Now they believe I am lying about all of it and is upset. There are also some other admittedly odd things that haven’t quite worked as we’ve been trying to answer this puzzle out. I have no answers, it is very strange and I can see how it would look like that but I’m not and honestly there is nothing nefarious about the website in their history. Idk what to do at this point as we haven’t been able to move past this or talk about anything else. It’s been three days. I really just needed to rant and get an outside perspective.