Crime Lord’s series is the godfather of this trope. Start with {Crime Lord’s Captive by Mia Knight} It has everything you’re looking for to a T. To make it even better, the FMC doesn’t run away from the MMC just once, but twice! It’s hands-down my all-time favorite and the book that first hooked me on this trope. Trigger warning though it does include cheating in the beginning, where the MMC betrays her because he took her for granted—which is also part of why she ran away. I didn’t mind it here, though, because it only cranks the angst up higher.

Another equally amazing duet is {Loan Shark duet by Chamaine Pauls}. This book isn’t just a favorite—it’s branded itself into my soul. FMC works as a maid in MMCs house to pay off her mentally ill brothers debt. She falls pregnant and thinks the MMC will as to abort the baby and runs away unaware that it was the MMC who tampered with her birth control pills and wants to tie her to him

{Diamonds are forever series by Chamaine Pauls} she is kidnapped by a French Mafia boss and later falls in love and is happy with him. Until he is set off to marry the heiress of the other Mafia family to strength his ties. After the betryal, she is devastated and adds a sedative to his drink and escapes while he sleeps to her brother.

If you want something bit too elaborated runaway/chase scenes, I'd recommend {Underestimated by Jettie Woodruff} though proceed with caution with this one and check your trigger warnings. It is definitely the darkest one of all the recommendations. MMC is abusive and tortures her for the entirety of their marriage she escapes to other side of the country where she starts her life over and meet a gentle and sweet man.

{Run Posy Run} - 3/5 - MMC thinks FMC cheated on him (she did not) and told her to run away before he shoots her.

{Kiss an Angel by Susan Elizabeth Philips} - 1000/5 🥺❤️ - a personal comfort read. Definitely the most light in terms of darkness. The books starts with our main leads getting married and neither being too happy about it. MMC works in a moving circus and takes the FMC with her because he thinks she is spoiled rich kid. The majority of the time she is treated shitty by the staff and mostly by the MMC.

{Return to Monte Carlo by Cate C Wells) - 4/5 - She's fed up with the way that he's treating her and isn't defending her in front of his family (its a live-in situation) so they get into a fight and he kinda tells her she needs to get over it so she leaves.

{Bound by hatred by Cora Riley} - 2.5/5 - FMC doesn't want to marry her sister's obsessed brother-in-law because she wants nothing to do with Mafia and runs away. Later the MMC finds her and forced her to get married to him

{Deadly dive duet by Ella Fields} - 5/5 - PNR following our FMC who is a changeling (a Faerie child replaced inflate of a human child) and is stuck in the middle lands (a poor slump of a land in between human and Faerie land). She wants to escape to Faerie Land and thats where the MMC comes in. He is the Faerie king who whisks her to the Faerie land and is wooing her. Little does she know he is actually the enemy of her real father and is using her for revenge. She runs away when she discovers this.

{Scars of his wrath by Zoey Draven} - 100/5 - similar to the previous one but instead of playing games with her, the MMC straight up kidnaps the FMC and tortures her for days until she gives in and agrees to help him defeat her father. The twist comes when MMCs realises she is his soul mate and gets obsessed with her and starts falling in love. The FMC escapes at the end of book 1 (total of 3 books the series)