Thanks for the tag. 
Portrayal of them accurately (to me, anyway) is very important and quite often not done, they’re bad criminals who conduct despicable crimes on both innocent and guilty people.
As for the LI, I think it’s more likely that if he was someone who wanted to leave that lifestyle, he’d be frowned upon by his family and perhaps even punished for it. He might be viewed as weak, unworthy, useless, the runt or the let down of the family etc unless he conceals it well but even then, it’s also probably likely that he’d be asked to conduct horrid crimes either way (if he conceals it well, he’d just be fulfilling his family’s ‘duties,’ if he appears weak and wants out, he could still be asked to perform them as a way to punish him or he might even receive torture or death). Perhaps they’d threaten to hurt or kill MC as leverage over him and a way to control him if they found out about her.
To avoid romanticization of the mafia in my opinion, he’d either have to be young enough to be innocent of his family’s crimes or was truly remorseful of any crimes he had committed (perhaps even became damaged) and knew his family + that lifestyle was dangerous, unlawful and in no way should ever be condoned or performed or even turn himself in (and/or his family) to face the consequences of the law, provided the officers, lawyers, barristers etc aren’t on their payroll already.
He’d still be putting himself and MC at risk whether he chooses to stay or leave (more so if he chooses to leave, especially for MC) and they’d likely require a protection program if he didn’t want to go to prison.