Leo Fitz and Jemma Simmons
Jemma and Fitz love have faced deep waters, other worlds, space and time. Fitz has always been in love with Jemma, while it took Jemma time to get there. They were both concerned about losing the friendship they share.
Fitz is an engineer, especially weapons technology, and Jemma is biochemist who specializes in life sciences. Together they work phenomenally as a team. After Fitz confeses to Jemma when they were trapped under the sea and came back brain injury, their relationship was put on hold, and by the time Fitz was healthy and could start a relationship with Jemma, she was transported to another world.
Fitz loves Jemma so much that he has been through time and space for her, making them Sueboohs Corner 2018 Countdown to Valentine day TV Couple of 2017 #5.
Here is a video of what Jemma and Fitz have overcome to be together: