Freeform is succeeding in all the places Cassandra Clare failed.
On April 29, 2016, Freeform's television series "Sadowhunters" made one of the most popular queer relationships officially canon in the realm of the TV show. This OTP (one true pairing) has gained fans over the course of the original six books that were later adapted into the television series, but fans who are new to the fandom are quickly hoping aboard this ship as well. And after episode twelve of this show, titled with the ship name "Malec" -- how could anyone not?!
While Alec Lightwood and Magnus Bane's relationship is moving much, much faster in the TV show's pacing, a lot of fans are arguing that Freeform's rendition of this relationship is already trillions of times better than the way the original author, Cassandra Clare, had written it. I'm inclined to agree, mostly because the writers of "Shadowhunters" are ditching a lot of the relationship elements that were problematic to readers of the books and altering things to make them more inclusive and overall making Malec a healthier relationship.
One of the most important factors is Magnus's character. In the novels, Magnus often shows impatience at Alec for not coming out of the closet to his friends and family. He detests being a secret and often makes snide comments about wanting Alec and him to go public. It's reasonable yes, but very non supportive on his part. However, in the show, Magnus is ready to be a secret. He doesn't push Alec to come out, but rather comes forward with his own feelings. While he doesn't support Alec's romantic pursuit of a female character, Lydia Branwell, he does not push the boundaries and never takes their interactions farther than Alec is comfortable with.
Another notable difference is interference of one of Magnus's old love interests, Camille Bellcourt. Because Magnus is immortal, he has pursued both men and women sexually and romantically and readily identifies himself as bisexual in the novels, as well as in the show. However, the book series enforces series bi-phobia in the form of Alec's suspicious and distrusting attitude of Magnus and Camille, afraid that he may leave him for a woman or that he will just sleep with anyone. The show tackles this issue much better, leaving out the bi-phobia and adding more of the fear that Magnus will continue to live long after Alec grows old and dies (which is a concern addressed later in the novels, anyway).
A key difference between the two mediums (books and television) is the placement of the big, public Malec kiss. It happens much later in the novels, before a a heavy battle, in front of a whole room of Shadowhunters and Downworlders alike. Obviously, since the show is in it's first season, we see this kiss happen during Alec's wedding to Lydia Branwell -- who is quite an amazingly supportive character seeing as she genuinely reassures Alec at the alter that he deserves to be happy and that he should go to Magnus. Seeing this kiss sooner is a big deal because it publicly establishes a solid queer relationship on the show, as well as to the characters adjacent to Alec in the plot.
Generally, their relationship is met with positivity in both realms, especially by his sister and his adoptive brother. However, in the novels, he is met with much criticism by his parents, especially his father. However, "Shadowhunters" challenges this homophobic plot line and replaces it with a similar issue, but one that's more prevalent to our society at the moment. Rather than his father being upset Alec is dating a man, in the show his mother disapproves of his relationship with Magnus because he is a Downworlder, which is a blatant metaphor for racism in the show, highlighted by the fact that the majority of Downworlders are played by people of color.
While there are plenty of differences that separate the show from the books, fans seem to be begging for more of the Freeform's changes, trusting these writers almost more than they ever trusted Cassandra Clare with their precious OTP. With season two confirmed to be released in March with a higher episode count of twenty to rival season one's thirteen episodes, avid Malec shippers can only hope there is more healthy Malec situations to come.