The best-case scenario is one where it turns out that Mike is a pushy, obnoxious individual, who will do anything to get what he wants etc. That is, he comes in finds/gets the book and leaves, possibly making a derogatory remark as he leaves. He wasn’t/isn’t a predatory individual, just somebody who acts that way. Along the spectrum of worst-case scenarios is that he rapes/sexually assaults you.
Often people are surprised that such rapes and assaults are even committed because the offender and the victim/target know each other. It seems like few people would commit such offenses as they can easily be identified, arrested and prosecuted etc.
The truth is that sex-offenders who assault people they know that they are able to put enough doubts in the heads of those they victimize that this is unlikely. Mike may, after an assault and just before he leaves, say something along the lines of, “If you tell anybody about what just happened, I’ll say it was consensual, that this was something you’ve wanted. I’ve known John since we were kids, you’ve only known him a couple of years. Who do you think he’s going to believe?”
When somebody is dealing with the immediate psychological, emotional and physical trauma after a rape/sexual assault, they may be susceptible to such ideas and suggestions. It may be that you resolve to tell your partner what happens when he gets home, but when he does you are not emotionally ready or prepared to relive all of this again.
It may be that you fear not being believed and/or feel to blame for letting Mike in the house etc. You may decide that this is something best left till the next morning after you’ve been able to sleep and recover somewhat. However, when that time comes, you realize that the “delay” could be interpreted as a period of remorse i.e., why didn’t you say something immediately, why didn’t you call the police etc.
You may be worried that if you tell your partner or friends etc., they will put pressure on you to go to law-enforcement and you will be forced to relive everything in a somewhat public setting (this is sometimes referred to as the secondary victimization which occurs when sexual assaults/rapes are committed). You know that there will be people who judge you, who think you are at least partly to blame for what happened.
Unfortunately, there are people who still hold on to the rape myths that we looked at earlier. Sharing what has happened to you with anyone, including law-enforcement, is not an easy thing and the longer you say nothing the harder it becomes.
Sexual predators understand all the doubts those they victimize have and how the criminal justice system finds it so difficult to prosecute them. Stranger rapists make “clearer” offenders, whereas with acquaintance rapist’s cases often get reduced to a “he said, she said” set of arguments. In a criminal case the burden of proof is extremely high i.e., “beyond reasonable doubt.”, and when sexual assaults are committed by people who know those they victimize, the defense will often try and paint the assault as a consensual encounter, which in many cases will mean that for a jury “reasonable doubt” will exist.
This is the unfortunate truth that means many cases won’t even make it to court even when law-enforcement believe that a rape has occurred.
If you identify that somebody is engaging in predatory practices, such as the ones described i.e., the grooming process, it is far better to take a better safe than sorry approach. It is far better to be overly cautious and possibly cause offense in a moment, which can be dealt with and rectified later, rather than have to deal with a sexual assault and the consequences that this may entail.
It isn’t “fair” that you have to deal with and navigate the socially stressful situations that either overly pushy men or sexual predators engage in, but unfortunately this is necessary in order to stay safe.