Dude, I actually do wonder how wild Noa was with her boyfriends. Seeing as how wild she currently is with a close friend
Did she like smother them literally with her boobs and buried their bodies somewhere?
Oftentimes when it comes to someone like Noa I think it's more like...being desperate but also not being desperate enough to completely go off the deep end? Noa wants to do whatever is necessary to maintain her fragile happiness. Except...she doesn't understand other people and assigns the worst possible scenarios to them. She doesn't do what other people say they want, but what she believes is necessary to be done to maintain the status quo. But that's it. The status quo is what state she is happy being in,
not the state her friend/partner is happy being in. The fact that Noa has never actually gone as far as having sex with any of her ex-partners is either the standard rom-com "They're a bit weird but they're a pure virgin" premise or a representation of how wanting someone to love you does not equal being willing to do anything for them.
I get the vibe Noa is more of a "1 month relationship that you extrapolate as much bigger than it actually was in conjunction with every failure prior" type of person than a long term relationship type of person. I'm not sure if she has actually gotten close enough to anyone to reach this particular point, especially from what was said last chapter where she seems to percieve Rihito being friends with her for six months (damn 68 chapters and it hasn't been a year?) as being an abnormally long time to be friends with someone.
On some level, I'm not even sure if Noa understands how she looks right now, her perception of relationships being warped in comparison to ours.