Haha, yeah, I enjoy pure romance, but given the choice, I do prefer a good external plot as well. Stories about couples falling in love while doing stuff like working together to solve a mystery or fight against some external enemy seem less likely to have some of the romance tropes I dislike the most, like jealousy and suspicions of cheating as a major factor causing conflict between the couple. Although of course I'm speaking very generally here and there's plenty of exceptions in both directions.