I gave a try to Memory Blue.
The start is pretty quick (around one hour to see the opening with Textractor + translation, and I skipped vanilla sex scenes with the future wife). MC is the average NTR salary man . He's in charge of a project team composed of a guy and a girl (the blond) who he knows since college. A new girl arrive in the team, and the MC fall for her immediately because boobas. After that, the time is pretty much fast forwarded until the end of the project (with some fractions of narration), you make a confession and she accepts because you're a good boy.
So yeah, it's kind of the start of Triangle Blue, but without the development after the confession. I would rather have an already established relationship and use the time of introduction to make the relationship feels "real" than lost time to make the MC stand gaping in front of his future wife for most of the introduction, fast forward most of the time and barely have any interaction with the girl to have her accept the confession out of nowhere, but at least it's not too long for nothing.
To cap it all, the future wife is pretty dull and dense like in Triangle Blue, so it was not very appealing for me. Blondie is easily best girl since she at least have a personality. And of course she's crushing hard for the MC who is completely clueless.
By the end of the introduction, you're married to the new girl and move together. And then, she's invited to a class reunion, she seems reluctant to go, but MC insists.
You have several choices during the intro. Most of them barely change anything in the dialogues/story after the choice, but it somehow choose who the wife will meet during the class reunion.
Unfortunately, I didn't really start the NTR paths because of a plot element that I really don't like in NTR stories : I'd like to be wrong, but I think you're forced to cheat first with Blondie to open NTR paths. If MC rejects her, you're lock in the boring vanilla good ending.
So yeah, it's a shame because even if the wife doesn't really appealed me, story and art seems good enough. I may give it a chance anyway since it seems there are two NTR harem endings with Blondie and Wifey falling for NTR "bad" guy.