Nah, Terry's not that kind of guy. He's the "tragic lover" kind of guy

I mean if you want to throw the Anime as "canon"

Terry loves Lily (killed by Geese), then Sulia (sacrifices herself, but then looking back she was only 17 so it's a bit creepy) and now Mary is his girl, even if they don't really go out and say it

Mai looks like she already has her arm around Terry, so now's her chance to pull his face into her tits and steal the letter.