Can it be narcissism, obsession or something else going on here?

Hi everybody, so my boyfriend and I had already talked about this and we kind of sorted things out, he said he felt comfortable speaking with me about it and so on, so I decided to give him a chance and start from there but recently I found out some things I didn’t know of which I don’t know what to think of. Below these lines I will give a brief explanation of my general situation, please read ,what I have discovered recently, it begins in the paragraph with a small ASTERISK (*) IN THE FRONT. Around June-August 2016 my now boyfriend as an engineer that he is, started working on a luxurious residential building on the beach where he met this girl that caught his eye big time, he has talked to me about this girl a couple of times now ( last time was February 2020). So when he spoke about her to me, he always started saying how beautiful,precious,model looking this girl is, that she had all these rich men sending her flowers etc, and that all the men that lived in that building were after her. He even said she had a “coke bottle body” , (she is a slim girl with a normal body but does not have a rocking figure as he claims she has, and this is not even like something to focus on this situation, it's the fact that, that he may still have the illusion of perhaps having something with her, if our relationship ends. I just can’t understand that why in the world would he even exaggerate this woman’s attributes/ characteristics, when I have seen some of her pictures and I know he is in fact exaggerating them, to me what I have seen, this woman is somewhat attractive, pretty, works in a nice place, maybe this makes him see her even more interesting, but shes nothing out of this world as he describes her to me. They began to fully talk more and more around Jan-Feb 2017 , they never ended up having a real relationship ( I wouldn't even say DATING for this matter) but I feel that he IDEALIZED their ''THING'' way to much and was deeply falling for her, to the point where he even called her BABE (as I saw in some conversations of the things I came across, and I repeat they didn't even have a relationship/dating, ( she had gone through a break up with her past boyfriend and then while talking to my boyfriend she found out that he cheated on her. I have to be honest, I couldn't resist on seeing their conversations, especially this being a situation that had been eating my head all along, I will repeat this word but he seemed very obsessed/infatuated with this woman. Like boy oh boy she caused an a huge impact on him big time. *So most recently I discovered that he has an album of her and this other girl he dated after her on his mobile gallery ( hes still has these 2 album on his mobile gallery) So recently I was working on an external hard drive he gave me to save and organize like around 10,000 pictures from his work( I help him out with his job due to high volume of work and he pays me) and I believe he had forgotten or thought he did not have those backup there I have no clue (YES MY BOYFRIEND IS VERY DISPERSE LET ME TELL YOU, FOR MOST OF THE TIME, HE HAS NO IDEA WERE HE KEEPS THINGS, HE LOSES THINGS EASILY, YEAH YOU GET THE PICTURE RIGHT!) The point is, that I saw on this external hard drive all backups of his mobile including including this girls name on a folder with literally 4 more folders inside ( with pictures of her, some pictures of the times they went out together, like 4 pictures of her in sexy lingerie ,( nothing too revealing), and screenshots of all of their conversations history of Facebook messenger. If you see the conversations you will see that he was literally throwing himself at her) this woman told him on various occasions, that she was heartbroken by her breakup plus finding out she was cheated on, so she did not want to date, neither play with him or hurt him, she was grieving and not ready, she wanted her space, nevertheless my boyfriend at that time kept on insisting that he was a great man, that he would respect her and love her deeply, that he loved her ( I'm shook. Anyways this woman said, I don't think you love me, Honestly I don't think he loved her either (to me it's called infatuation perhaps). she even told him : "you have girlfriend problems". and he replied :" I love your voice, your legs, your smile, your scent. " you left your scent on my polo shirt and I could not stop smelling it, ''I think about you every minute of the day'' "I cant wait for a new day to come to see you again'', plus much more crazy stuff like calling her ''MILADY'' like in the old knights days, to me it kinds of screams like low self esteem from his behalf ( like literally throwing himself at her like that) . I understand they had to see each other/interact, everyday for quite some months while he was working on that project in this building she worked in ( she was the project manager and out of all the engineers working there he was like the lead that reported issues to her, what they had fix all that stuff) that''s why so much talk between them. It seems this man was really into this girl or at least obsessed about her, cause from the way he talked to me about her and all this collection of her photos ( including sexy pictures), conversations and some pictures of them BOTH. Another thing I find very Strange is that he ALSO took 2 other girls he went out with after this girl to the building she works in, HE ALSO TOOK ME!! WHY?????? In the world? The other part that caught my eye and I cant quite understand ( maybe it's not what we SHOULD FOCUS ON HERE AS WELL,, BUT I AM PLAIN CURIOUS ESPECIALLY AFTER SEEING THE CONVERSATIONS,INTERACTIONS, THE FOLDERS I DISCOVERED ETC.Why in the world did this woman go out with him a couples of times ( like at least 7-8 times) to eat, to hang out, etc and CHATTED WITH HIM OH SO FREQUENTLY??. I mean if she was so heartbroken, why did she accept to go out with him in the first place ( this is I how I feel :'' If I am not interested in a man, I would not dedicate a second of my life entertaining him at all, ESPECIALLY ME BEING HURT AFTER A BREAKUP, I WOULD NOT WANT TO GO OUT WITH ANYONE ESPECIALLY NOT WITH ANOTHER MAN OR EVEN DATE!, UNLESS I AM READY TO MOVE ON!! ), why do you guys think she entertain him, was it an EGO BOOST FOR HER DUE TO HER BREAKUP, DID SHE ENJOY THE ATTENTION FROM HIM, OR DO YOU GUYS THINK SHE REALLY LIKED HIM BUT WAS AFRAID TO GIVE HIM A CHANCE (I think she liked him, otherwise I would not think she would talk to HIM AT ALL) . what do you guys think about all of this?

The main point is if someone offers you something free ,who wouldn't accept that ( not me though coz I Ain't a normie like your bf).Your boyfriend romantically cares for her but she doesn't . She's getting free attention ,free dinners ,lunches etc so she's using what she's getting . She's isn't desperate for anything but your boyfriend is. So the main victim here is you who has invested your time in such a meaningless person . Your choice is very poor. Next time Observe people first and listen to the environment without passing judgements.

2 things. 1. His obsession is unnatural, and quite frankly you need to just walk away. 2. It sounds like he is stalking this girl. You may want to warn her about his obsession.