Frenemies as Lovers

Black Sun's protagonists start as as enemies. In fact, Leonard is the prisoner of Jamal, a trope that many publishers and readers shy from. I find it at least more honest than some frenemy arrangements, in which the "hostage"-taking is purely emotional (one member of the couple feels indebted to the other). 

However, this type of frenemy relationship works best in historical romances. I admit to finding the current trend of modern-day protagonists in relationships with serial killing sociopaths to be a tad nihilistic. 

I prefer my frenemies to be rooted not in emotional enthrallment but in personality differences. Leonard and Jamal are complementary. In a far more modern setting, so are Minato and Shizuma from Therapy Game Restart. 

Minato in the "tacky" shirt

Shizuma bought.

Minato is smart, sharp-tongued, wary, self-aware, uncertain, quick-tempered, and dogged in his commitment. Shizuma is mellow, easy-going (despite being a hard-working and dedicated veterinarian), understanding, and easily romantic. 

Although their relationship is far more fraught with ups and downs than the brothers' relationship (Minato's brother is dating Shizuma's brother), it has grit--and believability. 

Frenemies in romance is best not as a state of continual uncertainty--but as a state of continual negotiations.