leaving aside for a moment the mechanics of jealousy, I have noticed often that there are folks who say "screw whoever you want, but I am not going to feel good if you fall in love with them", and others who say "have whatever emotions you want with the person, but I will feel very bad if I have to think about you having sex".
I'm not really sure there's a logic behind who thinks what - maybe it's just a wiring thing.
So I wouldn't be surprised at the apparent contradiction - just work on the jealousy as others are suggesting.
"Listen, or your tongue will make you deaf." - Native American Proverb