It’s not like it’s terribly uncommon for some Earth species or other to go from sexual reproduction, to giving asexual reproduction another try. What invariably happens is that the daughters only sub-species does well for a few generations, and then gets completely wiped out by some disease. We’re not having sex for fun, we’re having it because “applying combinatorics to our genetics (particularly the immune system genes)” is the best tool we have to try to stay ahead of microbes.