??

the girl wangwang thoughtlessly tried to help them without thinking about how her actions might look to others
yuyang saw her excitedly talking to lihuan (about their progress) and she suddenly talked to him without reason about how great lihuan is and what a great catch he is or to quickly confess or whatever-i-dont-remember (to make yuyang realize that he should get together with lihuan)
so if you dont know her intentions? it will look like she likes lihuan and pursues him
so yuyang who was finally able to shake off his insecurities started to have second thoughts again
what if lihuan started thinking that it was a mistake/phase/something temporary afterall, now that there was a girl who pursued him?
instead of getting hurt worse when lihuan eventually 'comes to his senses', yuyang decided it to be better to end their 'something' before he gets any deeper

it's a huge misunderstanding hurting both sides caused by a third party who thoughtlessly tried to meddle in affairs that got nothing to do with them

Just seen your reply, thanks a lot !!!