I caught my daughter having sex, please help

My daughter came out in college, and over break she asked if her girlfriend could come back with her. I allowed it. Since she's been at college I have had camera installed in a few rooms since (living room, kitchen, rooms with doors to outside). Well one day checking the security footage I caught them having sex on my couch, at first I was disgusted, but now I can't stop thinking about it. I watched the whole thing once and felt very guilty afterwards. How do I get past this?