Whether this manga was "good" or not honestly depends on what expectations you had going into it.
As a romance? I'd agree and say this is quite weak. Frankly, Saya hasn't shown any romantic interest in anyone throughout, not even her husband, and she's "straight" or supposed to be at that point in the story. Her priority was being set-for-life and conforming to what she's 'supposed' to do rather than the matters of her heart, and because we haven't seen anything of her growth we're kind of left with just the image we'd had of her until now. Her feelings towards relationships were that they are nothing more than transactional - what can I do for you and what can you do for me? It would've been nice to see her change her mindset and experience a true bond with Rei. Instead what we got was seeing poor, sweet, Rei suffer and then we skip to her being happy with the cause of her suffering lol. Wish we could've seen their relationship actually develop again.
If you view this from a psychological aspect... it's almost quite good? Better than the romance at the very least. It touches on a bunch of topics like a woman's relationship with her fertility, marriage, social standing in society and how important it is for women to be more than housewives... because if they decide to leave they have nothing. It also could've very easily breached into exloring comp-het if tthe'd developed Saya's character further past the time skip.
The reason I say it was almost quite good is because while they did touch on those subjects, they only scratched the surface. More could've been done and quite easily too because they'd set the ground work quite well. Personally, I always enjoy characters like Saya, plotting, conniving characters that aren't particularly likeable but they're not evil or morally corrupt just because. It feels like a waste that we didn't have more on her thoughts and feelings.
Overall, it wasn't a bad manga by any means but it left me wanting more in just about every way but especially the romance.