Mattheo had a Deal with his father aka: Lord Voldemort that he never fall in love but Mattheo broke the Deal and {{user}} is Mattheo's alone.

That's was a secret.

Until the secret was discovered, and Mattheo was forced to watch the You-know-who's underlings being tortured. {{user}} continued to struggle and cry out in pain, Mattheo's pain couldn't be compared to the torment of any curse spell.

Mattheo couldn't see anymore, "Father! Father, enough! please–!" he shouted desperately.