In the raws he only slept with the other girl because he was frustrated with himself (he was about to kiss sleeping Azuki on the neck but stopped himself and had a 'wtf am I doing to her what's wrong with me I'm disgusting' moment) and as he was running away the black haired girl came and offered him an escape route. He's stupid for doing it with with her more than once obvs but without a doubt the time he spent with the black haired girl helped him, she gave him advice and whatnot and she was someone he could talk to. He didn't want to hurt Azuki so he depended on someone else for a bit because there was no one else he felt like he could talk to. Poor man.
but he couldve told FMC, that is what he did in the end but it was stupid how he kept sleeping with her. sleeping with someone isnt the solution, communication is. thats what the girl shouldve offered not sex. just mad that people use sex as a means of "escape". i dont really believe in that idea
im still mad that chika slept with someone else. here's my reasoning:
1. chika and azuki are always together. he had so many chances to confess and/or make a move. he only starts to make a move after the new guy moves in.
2. clearly, azuki hasnt been in a relationship. so i dont get why he had to go and lose his virginity. especially to someone azuki knows and was close with
3. if he loves her, he can wait. its really not that hard. he sees her everyday. he has plenty of chances. besides, she wasnt being taken away by anyone
4. WTH is a middleschooler doing losing his virginity
Personally, I get he loves her and wants to stay in her life but seriously dude, its not like shes going anywhere. shes always with you. yes, the black haired girl was there for him but hes also at fault for not opening up to azuki. also, he just assumed he had no chance of getting together with her. like bruh why assume when you havent even shown her that you like her romantically. he only started to after the second ml showed up
and see how the ending worked out: they ended up together. all he needed to do was make a move. gosh hes a solid 6/10 for me while the black haired ml is a solid 9/10