I'm able to change characters, setting and plot quite easily, but when it comes to the erotic stuff, I find the exact same. Apart from some tweaks with how the characters interact with each other I feel like I'm repeating something I've written before. I find myself very invested in a story until I get to the sex bits. It might be a good idea to try writing regular fiction and see how the characters play out without the sexual dynamic.

I think it's more likely that UFO sightings and abductions are actually the US military conducting top secret experiments on weaponry and people