<human>: Can you condense the text into three sentences or less?

So my SO and I have been dating for 2.5 yrs. During that time, we decided it would make sense for us to move in together to save money on rent and get to know the joys of cohabitation.

For the first year we lived together, we shared my laptop. It was the only computer in the household and, while it bugged me at first that I had to share, I eventually got used to it. 

Cut to present day: GF now has her own laptop, I have mine, and I just built my own desktop. Over the weekend, my lady started using my newly built computer without asking me about it. I kind of playfully gave her shit about it but didn't escalate it to the point where I let her know it irked me. I came home tonight and again, the woman is on my machine. 

Needless to say, I'm not thrilled about this. I bring it up directly and request that she ask me to use the computer before just jumping on it. I think this is a reasonable request - she's not speaking to me because she thinks I'm crazy / hiding something. 

Reddit, am I out of line? If we each have our own computers, is it weird that I'm protective of my new machine? Do you let your SO's use your computers?
<bot>: GF has her own computer but has recently started using my newly-built rig and now we're fighting about it. What's your experience dealing with this?