Does anyone know if Marissa Castelli and Marvin Tren retired?
You should check out U.S. pairs thread more often. Also, IceTalk episode #20 has an interview with Marissa and Mervin that's interesting and revealing. It took place after 2017 U.S. Nationals. They were still very committed to their partnership at that point, but were also understandably disappointed about being overlooked for 4CCs selection and Worlds alternate that year:
http://web.icenetwork.com/fans/icetalk
As a team, they gave it their all, but they had a lot to overcome. Things were not going in their direction almost from the beginning because they couldn't compete internationally for a year. Then the initial coaching set-up of trying to work in Montreal and sometimes in Boston was not the best decision. The scoring was political in their first competitions in Canada, IMHO. And then, Marissa (as she said in the IceTalk interview) found it more difficult to adjust to a new partner than she'd anticipated. It was like starting over from scratch in some ways, especially due to needing to get used to each other in competitive situations which takes time.
C/T's partner tryouts together went exceedingly well and they enjoyed skating together and were well-matched physically and temperamentally, but maybe their jump techniques were dissimilar? Marissa also did not have as varied an arsenal of throw jumps as she should have had. So they had to work on that, as well as on fixing timing problems with their sbs jumps, etc. Their technical issues were apparently either not noticed soon enough, or not addressed soon enough. And then there was also the citizenship hurdle for Mervin which takes time. So, the fact that Mervin was not eligible for the Olympics likely factored into them not getting a competitive assignment after winning the silver medal at 2017 U.S. Nationals. Of course, their unresolved technical inconsistencies did not help their cause. With all of the problems, their confidence suffered. I think the car break-in where their skates and Marissa's costume was stolen after 2018 U.S. Nationals in San Jose, was perhaps the last straw in a string of partnership misfortune.
Their split is sad because they were one of the best stylistic teams in the world with great speed and wonderful blade skills, plus a smoothness and a sexy chemistry on the ice. This is one of my favorite C/T performances:
https://www.youtube.com/watch?v=nVAqIyTNpCU