i'm sorry about what you went through and i'm sorry about the invalidation of these problems and pain you went through that you recieved along the way. it's easy for someone to say "just move on" as if it's any other problem; it's easier said than done.
you can look to therapy, counselling, all these things to somehow "move on" or get better.
but honestly, will any of these find you peace? will they give you this peace of mind that you're looking for? will they stop you from you're obsession towards him? i just think it's always gonna be there no matter what you do, the thoughts of what he did and who he is and the fact this person's out there roaming and happy and free to do whatever he wants, while you're still suffering.
i really do believe you need some sort of closure and peace of mind to truly be able to move on; and by that, i mean being able to finally do what you haven't been able to do, somehow speak up and face what he did to you, so he deserves what he gets and you deserve the justice you recieve; and you finally see him rotting away where he deserves, jail, where he won't be able to hurt anyone else.
who knows what he's done to his girlfriend, other girls, and people potentially in the future. he's done it once, who's to say this person won't do it again?
it's absolutely the hardest thing to garner the strength to be able to speak up and face the very thing that's hurt you. i completely understand. but you're at this point, where you don't wanna die, you don't want him to WIN. And you wanna outlive him, but how much will that do in terms of bringing you peace? how much will that do in terms of him still undeservingly living life because he clearly has absolutely no remorse for what he did to you?
talking directly to the police isn't the best starting point. you wanna talk to someone who understands you, can actually validate you're pain and suffering because they've also gone through it. you deserve to be heard and understood. i'd suggest reaching out to rape crisis and sexual assault services locally, to be able to comfortably talk about it with someone who can actually understand you and what you're going through and go from there.
it takes decades, years in general for rape and sexual assault victims from both genders to speak out. it's the hardest thing to do. yet there comes a point in their lives, where they just finally want peace and nothing more, and they want the person who did it to finally get what they deserve.
this is completely just my opinion and how i feel about this, and i would definitely understand if you ignore it.
i hope you find the strength to be able to speak up someday and put this pathetic human being in his place and where he deserves, so he can pay for the hurt and suffering he's caused you and potentially others. and through this, i hope someday, you're able to then finally have a peace of mind and find peace in general.
take care.