Is it normal to have sex with your imaginary friend?

Thanks for sharing your story. Yes I did read through the whole thing xD
Funnily enough, I never had imaginary friends as a kid either. I did used to make up my own imaginary world and make up people and even animals, but they weren't like imaginary friends, like I wouldn't interact with them, I would just make them up and create their lives, their back story, qualities, favourite things etc etc.
And also surprisingly, I am not an only child. I have an older brother (26) and a younger sister (9) so it's not like I never had anyone to play with when I was younger.
However, I was lonely. And that loneliness manifested itself as Yukiyashi. I believe that I created him to fill a void that cannot be filled in real life. I am also only attracted to East Asian guys.
Yukiyashi popped up when I was 16, when we moved as a family to the countryside, however my brother wasn't living with us at the time. And I truly believed I would never find anyone who I would fall in love with. I've had guys fall in love with me, sure, but I've never felt the same way for them. And it breaks my heart each time to say no to them, yet wanting to still remain friends. And it would be hard to meet anyone remotely like Yukiyashi in real life, specially where I am now. I am pretty much incompetent and useless, I can't even do simple things like cooking or washing. I've never needed to, because I live with my parents. And I am tentative to try new things. Even though my dream is to travel to Japan, I don't think I will ever get to go and if so, how would I find someone there?
So I have stuck with Yukiyashi. I also have more invisible friends, including Naoki, his sister. She is very hyper and bubbly and fun.She has OCD. Then there is Nguyen, Yukiyashi's friend from South Korea. He is a kind of a nerd and wears glasses, but he is a "cool" nerd, like even though he's a genius, everybody thinks he is hot and wants to be his friend. He has brown hair and black-rimmed glasses, and is very ambitious, confident and sometimes sarky. I think he may have Asperger's syndrome, although it's not confirmed. AND then there is Kim Seung-Hyung, who is a defector North korean soldier who is actually Nguyen's half brother. He braved his way across the border to find his father and get away from his fate, where he found Nguyen, his half brother. Nguyen, shared the same biological father with Seung-Hyung, as his father did the same and ran away from North Korea. Seung-Hyung (or Kim) can be very highly-strung and gets angry often, but he does have a kind heart deep down. He also has a really sad story. He grew up as an only child with only his mother to take care of him, and they were very close. However at eight years old, he had to watch his mum be killed in a public execution - for stealing a loaf of bread in order to feed him as many of North Korean people live in poverty. He was then taken to a prison camp and tortured for being a family member, where he later managed to escape and find a kind man who gave him food and shelter in exchange for work.
And the newest addition is Kuso, who is a ghost. He is the first of my imaginary friends who is technically "dead", however I still see him as a human being. Because I created him because I craved human male companionship, like all the others. Anyway Kuso is a ghost. He is also Japanese, like Yukiyashi, but he is an albino. He grew up only with his mother, who constantly ridiculed him for his appearance and how useless he is, and sometimes even beat him. His father allegedly left Kuso's mother when he found out she was pregnant. So she took her anger and resentment out on her unwanted child. He was also a laughing stock at school and badly bullied, and the teachers were always having a go at him because he is bad at studies. However the one thing that he can do is play piano, putting all of his feeling and heart into the piano playing. Sadly he killed himself by slitting his wrists in his room one day after being bullied, and because of his depression and self-hatred. Now he is a ghost, or an angel.

To make a ludicrously long story short (it wasn't short, sorry): As a child I grew up as a only kid until age 7, during the first 6 years of my life, life was so-so. I was sexually assaulted at a daycare around age 4 by a male child and a male adult. Moving in to 6 I was assaulted again by two more male classmates, and that trend followed with various individuals up until age 10. (I say assaulted as a stand in for the word rape because I was also assaulted by four former female friends and it technically is impossible for a girl to penetrate another girl without the assistance of a object, excluding hands, were In from the law classifies anything else except for penetration of a penis in a vagina as sexual assault, because laws are bull sometimes, moving on)

The trend stopped when I started dating the guy who went on to be my late boyfriend/fiancé. He offered me protection (literal protection, and no he was not a child) however the damage was already done. (Now I'm not saying all this happened to you as well, that's why I suggested people skip on down. This is just some backstory to help you better understand me and figuring this out also helped me figure out many things about myself)
(Part 2)

I know ^^;;

there is no need to get so aggressive, Jesus Christ. This is why I don't like real people. And this IS "is it normal" where weirdoes, hang out, right?

19 is still a teen lol. nine TEEN.

Yes he's the only boyfriend I've ever had
No I've never seen another guy naked IRL (unless you count porn)