how to handle these sick peeper

Tell the person not to do this.

(why were they able to to do this? doesn't the washroom have a locking door?)

thank you so much for your prompt reply. actually, the door cannot be locked. i rent one of the room and before that she said her bf may come here sometimes, so we got a rent deal. but now he comes here nearly every day.
i do wanna face him directly and ask 'are you on purpose just now'. but i just dont want to make it awkward with my roomate. so i will talk to my roomate tommorrow and let her handle this.

You can still tell this guy to stop ogling you. If that makes it awkward with the roommate, then it does. You need to look out for yourself.

Why are you concerned about roommate's reaction? You are certain that he was doing this, right? He violated your privacy! What's more important to you? your roommate had better understand what is going on. This man has to be stopped from doing this.

Furthermore, it's relatively easy to install a simple lock for the door.

Your roommate wasn't the peeper. The boyfriend was. You need to talk to the peeper - perhaps with the roommate in attendance.

but ... the boyfriend is the one you need to talk to

and

put a lock on the door.

Yes, there are simple inexpensive types of locks or latches.

thank you for all of your sweety advices. i do feel much better. you know what's going on now?
i have a talk with my roomate and ask if her bf can come here not so often. i am single and i do not think i am ok living with a stranger guy balabala…. then she said, 'sorry, and you might be scared last night'. it is out of my expection that he should confess to her. Then she balabala…

so i just know the reason why he comes here so often is that he has no place to settle. God. then i tell my romate i agree he lives here till he find a settlement. but you guess what, upon words come out my mouth, i swear i regret.
so here comes the question,
am i wrong thinking him as a sick peeper,
or he is not a simple peeper and deeper than what i think?
more thinking, more scared.
and he still lives here now.

There literally is NO way anyone here can answer these questions not knowing if any of the activities are still occurring or not. Perhaps an ultimatum needs to be put down (set time limits and rules regarding your privacy and when he can stay if your roommate isn't around). And necessary measures need to be taken: appropriate locks on the bathroom door and your bedroom.

Just curious? Is this guy autistic or something?

Really cheap way to secure a bathroom door or bedroom door. Very easy to install.

Next time you're in a living situation, don't volunteer such things and don't agree to them unless there is something in writing. What should be in writing? Specifying how long the guy will stay, what he's paying for (groceries, utilities), what his rent is. And make it abundantly clear that your bedroom is off-limits to him unless you invite him in, even if your roommate is with him and he needs a book from your bookcase.

Install some simple hook and eye locks. They are cheap and easy to put in.

STOP BEING A VICTIM.

You do not owe this guy or your roommate niceness and concessions and letting them walk all over you.

Roommate situations are hard enough without introducing someone into the mix who has an open-ended invitation to hang around, doesn't seem to have any obligations to pay for anything, and also seems to be clueless as to physical boundaries.

er, autistic? may be or not. i am not sure. he cooks for her girlfriend and does cleaning work. sometimes, he often shows being over nice. serveral morings on weekends, he knocks and asks would you like share breakfast, or bring some snacks or tell me the wifi code he just reset. well, it's wired. don't he know he has a girlfriend to care for. so everytime he tries to talk to me, i just answer yes or no.

i will make a rule with them and start to find a new roomate.

i guess i got the feeling of being single, traveling and loneliness and missing the ex.

actually, my roomate counts the utilities, and we three share. cause she thinks her bf indeed lives just as long as we both. they deserve it.

i just cannot to be the one to hurt others. i do think i am always the victim. so to protect myself, i just tend to avoid something and someone. and i start to doubt if i can protect myself well untill i meet my prince.
sorry to let you share my weakness.

Why haven't you commented on whether or not you'll be putting a simple lock on the bathroom door? There were a few people that suggested it and photos put here about inexpensive latch that could bought and installed for next-to-nothing? No handyman needed - just a screwdriver. Why no comment?

sorry. i just dont want to make it so tense. the lock means how dangerous condition i am in. i dont want to send this signal to myself. but trust me i do appreciate your lovely care. And i am looking for a new roomate.

he did not peep stealthily, he just opened the door and said sorry calmly , he thought the one in shower is his girlfriend. that is what happen at that night. although i tend to believe he is on purpose, i am still not sure.

i promise i will protect me better. i mean it.

You are basically saying... if I read your post correctly... this incident only happened once? And you're ready to crucify both boyfriend and your roommate (for what now appears to be an honest mistake)? Perhaps you yourself aren't the ideal and perfect roommate either?

Frankly. you're story is very confusing. I can't understand why you won't take any action at all. There's a way to help protect your privacy with a simple lock (did toy see the pictures?) on the door. Simple process with minimum investment of money and energy. That's just inconceivable that yo won't take any action. While I've not been in a house with no lock on a bathroom door, I imagine such a place exists.

I am thinking that you are "always the victim" because you prefer not to stand up for yourself with others. Standing up for yourself is not hurting them - it is telling them who you are and what you think. If you don't learn to do this, you're apt to have further such troubles in life.

I am guessing you are easily frightened, that you are jumping to assume this guy is some kind of pervert. I suppose it's possible, but not clear from your description of what happened.

yes, it did not happen before.
no, i am not gonna crucify anyone. i just wanted to speak it out to look for some comfort or advice when it happened. at least, i felt being invaded at that moment.
yes, i am certainly not perfect.

sorry for the confusion. but do you really think a simple lock can prevent you from those who have the intention to bother you. or maybe i choose to believe it is just an incidence and let it go. i don't know.