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Well, Gisela gave MC the chance to confess and to finish things for her, preferring a less hurtful way instead of having to witness ML running off and leaving her behind like that.

That’s also why ML felt played by both:
Gisela knew that he harbored feelings for MC before he himself did, so she started treating him differently.

And MC thought that what he did was out of consideration for ML, but tbh it seems to me that he made it out of self-consideration (not confessing when the given opportunity exists).
MC believes he did a good thing by not confessing to ML and excused it with “I did not want to influence your choice“, but that does not make any sense EXCEPT if he were to be convinced (= sure about) that ML will come for him TO BEGIN WITH.
That’s why ML now questions MC, his made choices and how much he can even trust him.

In the end both, Gisela and MC, put ML in a difficult and awkward spot (which was really not necessary) while him being clueless about everything.
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And yes, it’s important to note that both (Gisela and MC) had most likely their reasons for these self-considering choices, probably not wanting to risk any kind of loss, which can be not being able to avoid a painful parting->rejection.

Could have been a question of pride too (like ML pointed out)

I kinda agree, after all, confessing is up to the person, regardless of the reason. Also, although I haven't read this in forever and barely remember anything, if Gisela already knew that ML was in love with MC, then she should have been the one to walk away first right? Instead of trying to get MC to confess to make it less hurtful for her because her leaving first, after finding out, would clearly be less hurtful. I don't really get it.... cause they like to over complicate things in stories....

Yeah agree like me liking u doesn't mean I will tell u hahah, and the gf should have talked it out with her fiance u guys are the ones in relationship that was led to marriage. The ml could talk it out to gf to like u have feelings u don't know how to address to a friend of urs then tell the girl u were in talk the marriage about it, no? why drag it i mean if they (ex gf and ml) were just dating i would kinda maybe understand But guys you were about to marry

I mean it’s not like she didn’t have any feelings for her fiancé at all? And that’s why she also brought up that MC should confess, because she wanted to see who ML would chose. She was pretty sure he had feelings for MC, just himself not being aware of it. She couldn’t have simply left, because of smth she wasn’t even absolutely sure off, but she couldn’t either go to ML and say „Ayo I don’t think you love me, I think you are in love with your long time friend“.