A lot of answers are talking about what women writers get wrong about writing men in general or straight men in particular. A few are talking about relationship dynamics. I’m going to talk simply about sexuality, a simple aspect that a lot of women writers get wrong because it’s subtle. I saw yet another example of this in Bridgerton on Netflix recently.
The two characters above, Daphne and Simon, pretend to be in love with each other. Supposedly, this will accomplish two things: First, it will get real suitors to start pounding down Daphne’s door, since someone else stole his thunder. Second, it will get the mothers of the ‘ton to stop bugging Simon about getting married to their daughters.
This isn’t how male heterosexuality works.
Heterosexual women, on seeing that other women are attracted to a man, tend to find him more attractive. Having a girlfriend or wife can make a man more attractive to many women; studies generally show that at least some subgroups of women (e.g., younger single women) engage in mate choice copying and mate poaching behavior.
Female heterosexuality tends to lean heavily on social proof, social status, and social relationships. Other women being interested in a man is proof of his quality. This is part of the reason why divorced men are more likely to marry than never-married men of the same age (or divorced women).
This is a real phenomenon among women; romance writers often make the mistake of generalizing it to men in various ways.
Male heterosexuality does not work this way. If anything, having a boyfriend tends to ward off male attention. Men often want to be a woman’s first love. They’re much more likely to be interested in virginity and innocence, less likely to be interested in sexual experience and social status. (That’s not to say that men are immune to group-think or fads regarding what should be considered attractive—but, unlike with women, mate choice copying is not consistently visible among men or any notable subgroup of men.)
Realistically, Simon and Daphne’s ploy should have backfired. Daphne’s other potential suitors should have been warded off instead of instantly reinterested. Who wants to compete with a duke for the attention of a woman who is already besotted with him? Simon actually expressing interest in seriously courting a woman, instead of putting him off the market, should have led to the other daughters of the ‘ton setting their sights on him and their mothers pestering him with a flood of invitations and hints.
A few relevant studies:
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.173.1978&rep=rep1&type=pdf
https://psycnet.apa.org/fulltext/2012-24855-005.html
Mate Choice Copying in Humans: a Systematic Review and Meta-Analysis