Yuutarou Terada

Yuutarou, nicknamed "Yū" and "Tera" by his peers, is one of Ren's friends at school and is both sagely and mature. Unlike Ga-chan, he tends to be more realistic and is often holding back Ga-chan's matchmaking attempts so as not to trouble Ren. In middle school, he attended the same cram school as Sayuri Uehara, and they began dating. However, they broke up abruptly when Sayuri believed Yuu was cheating on her. Yuu regrets hurting Sayuri and realizes their relationship failed because of lack of communication, but knows they cannot return to the way they were. Instead, he encourages her to make peace with Daiki when troubles appear in their relationship, and moves on from her once she has done so.

(Source: Wikipedia)