Yes, there ARE people in Terriermon's life besides Jian!
Shaochung (another Chinese name - spelled and pronounced 'Shiuchon' in Japanese letters), Jian's little sister, is an innocent, childish being seemingly without a care in the world. Being a little girl and all, it's only natural for her to have taken an extreme liking to the cute and cuddly Terriermon. Because of the general lack of knowledge of Digimon being real, poor Terriermon is forced to pretend to be a stuffed animal whenever Shaochung is around, and boy does Shaochung ever take advantage of that! Terriermon is her very favorite plaything in the entire world, and she loves to dress him up and pretend that he's her baby. She's not exactly a careful child either, so Terriermon has to endure endless ear tugging and mouth pulling. Moumantai, Terriermon!
Despite the trauma of being lovingly abused, Terriermon DOES care for Shaochung, and WILL put up with her abuse to keep her from crying, as well as protecting her if he needs to. It's a bit of a rocky love-hate relationship, but deep down he does understand that she's just a little kid.
Jian's father, Mr. Lee, was the one who got Jian the computer game in which he met Terriermon, and you know what? Mr. Lee just so happens to be one of the nerds who worked together on the Digimon project back in the eighties! Wow, what a coincidence. Naturally, he is very knowledgeable when it comes to Digimon, and once he found out that Terriermon was real all along, he became a big help to the kids and their Digimon partners.
Takato & Guilmon make up another Human-Digimon partner pair, and are Jian and Terriermon's best friends. The two pairs first met back when Takato still had problems getting through to the very young Guilmon, and Terriermon made a blunt remark about Takato lacking what it takes to be a Digimon Tamer, resulting in Takato running away in tears, obviously jealous of Jian and Terriermon's beautiful friendship.
Well, thankfully that's all in the past! While the timid Takato can rely on the calm and collected Jian, Guilmon is Terriermon's playmate. The two of them have a blast together, sometimes joined by Culumon. Guilmon's hobbies are similar to Terriermon's, but Terriermon is a lot more experienced and independent. Despite their differences though, they get along great.
Lopmon is a Digimon nearly identical to Terriermon. He started out as a Perfect-leveled Digimon named Andiramon, a part of the Deva group. This group was based on the Chinese zodiac animals, and was out to rid the world of Digimon working together with humans. Andiramon represented the rabbit. He met Shaochung when she first stumbled into the Digital World, hung out with her for a little while, and eventually grew so attached to her that he betrayed his fellow Devas in order to protect her. Shaochung got her Digivice, and Andiramon devolved into Lopmon, officially becoming her partner Digimon.
Now that Shaochung has her own Digimon, it looks like Terriermon can finally catch a break. He sympathizes with Lopmon a lot, and the two of them can often be found looking at each other and sighing. Their interaction kind of only goes that far, though. Despite looking alike on the outside, their personalities are nothing alike - Lopmon is serious and not very used to modern lifestyles, resulting in a slightly awkward personality.