books depicting or discussing the complexities of friendship?

hello 🙂 as the title says, i am wondering if anyone has a book recommendation that might help me think about/process friendship ~

if you want more detail:

i am a young adult and i have been in a relationship for over 6 yrs and that partnership is based upon a solid, trusting, goofy, amazing friendship. we are best friends in love. it rocks 🙂

outside of that relationship, however, ive struggled to make very close friends as an adult. the last best friend i had (not including my current partner) was in high school and it was a very unhealthy dynamic; she was my best friend and my bully at once. since then i’ve had lots of friendly acquaintances and some that are closer but no one who was my 🤞 person in a non-romantic sense.

over the past few years i’ve been really wanting to make close friends and getting insecure about my failures to do so. i feel like there are rules i don’t understand to friendship and i don’t know how others do it.

then, about a year ago i met & became close with a coworker! we began to hang out a lot and learn more about each other and we have come to consider each other best friends (she is friends w/ my partner too but less close). i’m in a place in my life where friendship is a huge priority for me and my romantic relationship is very stable. when we met, she was single and not really seeking a partner, so we both became big parts of each other’s lives and it felt like this friendship was a major focus for both of us. we talked a lot about how friendship works and how to build this relationship. i still felt like i was “doing friendship wrong” sometimes, but she gets that and wanted to learn with me how to love each other well.

two months ago, a guy came into her life and things have been different since then. we’ve talked a fair deal about it, but i still have so many complicated feelings and i need a way to deal with them outside of talking to her because i really want her to just be able to enjoy this new relationship and i want to be a good friend. the bf seems really nice btw, and she seems so happy, even if things feel like they’re moving quick from my pov. some of the thoughts swirling in my head are along the lines of:

how do we, as adults, navigate platonic and romantic relationships?

what do you do when someone you were getting to know as an individual is enmeshing with a romantic partner and becoming “we” and “us”?

how do i fit into my best friend’s life now that she has a partner? (even though i have a partner, too!)

why is romantic love considered so much more intense and life-altering? if he is like everything and more to her in 2 months, what did my one year of friendship mean? why do people act like romance is the only way to have very strong feelings?

can friendship be as important as romantic relationships?

how does friendship work????? am i doing this wrong?????? i feel evil for not being just purely happy for her!?????

how do i be a good friend while im feeling all this not so pretty stuff?

TLDR; im looking for: explorations of messy, intense, and complicated platonic (!!) feelings, friendship as the primary relationship focused on in book, feeling the “wrong” things/too intensely, dealing with changing relationship dynamics, human connection, jealousy, grief, why tf do adult friendships feel so difficult, struggling to be a good friend

i like ALL genres/time periods!!:) unfortunately i can only ready english:(

if you read any of this i am very grateful <3 i hope you have a nice day 🙂