My heart felt heavy reading through the entire thing as I feel like I could relate to parts of the plot. I had a similar situation where I had my first ever relationship with a girl who's already been in multiple, and god was the initial phase of the relationship hard to get by for me. This manga just made me remember about how ignorant and closed-minded I was at the time as I felt like back then, if I wasn't her first then I wasn't her best, but having that type of mindset was unhealthy and I could only thank her for having me come to that realization. To tie this to the manga, I just feel like a lot of people overlook one of the important aspects of having a healthy relationship which is helping each other to grow for the better. Meguro was shown to be a character who showed little to no emotion and had this outlook on love as if it were insignificant & unknown to her despite being in so many relationships & flings until she finally meets Koga who helps her to finally open up more (albeit very, very slow) and experience what love is truly like.
Anyways, I just wanted to get that off my mind and chest & now comes my actual review. Meguro-san is very, very average. The plot was promising at first as it's not often you see this in romance where an inexperienced boy + experienced girl get together and the two seem to be new to the whole relationship thing despite one of them already being in so many past relationships. It also felt a lot more "mature" compared to a lot of the other romance plots, yet it fell short. There wasn't many significant trials or tribulations that the main couple had to go through in order to further develop their bond with one another until the very end (which honestly was very unnecessary, rushed, and very much uncomfortable). It honestly felt like that the two were growing without having to really do anything, which isn't necessarily a bad thing but for a fictional work it's just very boring. I also disliked the author for trying to push this narrative about Meguro's first "love" as if it were innocent & pure when we all know that it wasn't. The sensei (Meguro's first "love") was a literal sack of shit who exploited her for her body and never had any type of feelings towards her. Yet despite all of this, Meguro seems to hold him in a positive light? Make it make sense. Honestly, it would've been nice for the author to explore that part of the story and maybe could've had Koga help her to realize the wrongdoings that the sensei has done towards her.