I am also looking for a yaoi manga.

It’s involves two college students were one is a model and the other one has a crush on him since high school and decides to steal his high school girlfriends so he can have him all to himself. The model is straight and had bad luck with his gfs and when he finds out his friend had crush on him he decides to date him. The model is light hair and decides to date his friend who is dark haired and wears glasses. There is an event when an ex girlfriend bothers the dark haired guy and threatens to ruin the models face. He called the model and broke up with him and so the model decides to go to his house with a friend and try to save the dark haired guy from the crazy ex gf.

Sounds like Tonari ni Iru no ni, Tooi by MINASE Masara.