You're entirely compromised in this situation. Your judgement is not sound on this one and your question illustrates this clearly.

You obviously felt it was perfectly acceptable to get as intimate with this human being as is possible, and suddenly today he's a user/abuser and you're super concerned about all the poor vulnerable women at your company and keeping them safe from this terrible evil man.

The only non-head-in-the-sand, non-misandric answer to this question is that you're embarrassed that your personal life walked right into your office at work, and worse still, other people want it stay. You're not at fault professionally here at all, but you're going to definitely be at fault professionally if you decide to torpedo someone's career because you feel uncomfortable, and only for participating in literally the exact same activity that you did.

The only correct thing you can do is explain that you don't feel the candidate would be a good fit because there is an existing personal relationship. Or, express that you don't think they're a good fit and don't offer explanation. Whichever route you choose, sit back after and deal with the outcome professionally as well.

At the end of the day, this is a tough situation but it needs to be handled professionally. Torching someones reputation to hide aspects of your personal life is hardly professional.

You're entirely compromised in this situation. Your judgement is not sound on this one and your question illustrates this clearly.

You obviously felt it was perfectly acceptable to get as intimate with this human being as is possible, and suddenly today he's a user/abuser and you're super concerned about all the poor vulnerable women at your company and keeping them safe from this terrible evil man.

The only non-head-in-the-sand, non-misandric answer to this question is that you're embarrassed that your personal life walked right into your office at work, and worse still, other people want it stay. You're not at fault professionally here at all, but you're going to definitely be at fault professionally if you decide to torpedo someone's career because you feel uncomfortable, and only for participating in literally the exact same activity that you did.

The only correct thing you can do is explain that you don't feel the candidate would be a good fit because there is an existing personal relationship, or recuse yourself from the process because of a prior personal relationship. Whichever route you choose, sit back after and deal with the outcome professionally as well.

Another thing you need to consider beyond your own personal feelings is the company itself. I think by not immediately recusing yourself, you've possibly opened the company up to a lawsuit (depending on locale). If the candidate isn't selected, he could claim that you and your relationship are the reason. If he is hired and then dismissed, he could claim this as well.

At the end of the day, this is a tough situation but it needs to be handled professionally. Torching someones reputation to hide aspects of your personal life is hardly professional.