Warning: contains spoilers for Fantastic Four #46!
The Fantastic Four's leaders have never truly had a stable marriage, and Reed Richards finally reveals the exact reason why he has so much trouble being life partners with Susan Storm. Marvel's 'first family' travel to many exotic places on Earth, space in different dimensions, timelines and Multiverses, but Reed and Sue's biggest struggles occur at home. Fantastic Four #46 reveals that Reed has a serious communication issue that seriously hinders his efforts to maintain his marriage - and Sue Storm's respect.
Reed Richards and Susan Storm were two of the first comic book superheroes to be depicted in a stable relationship (they were engaged as far back as their first appearance in Fantastic Four #1 in 1961). The pair were eventually married in Fantastic Four Annual #3 and have remained so ever since (minus multiple divorces and reconciliations in various alternate universes), even raising children of their own. Unfortunately, the marriage is not without trouble, and Reed has immense difficulty talking about any of his feelings toward Sue - or anything else.
In Fantastic Four #46, written by Dan Slott with art by Cafu, Reed Richards finally unites with his long-lost sister, Joanna Jeffers. Reed immediately picks her up in his ship while Joanna is on a research expedition in the middle of the ocean. "Where are we rocketing to now?" asks Joanna. "Wakanda? Mars? The Negative Zone?" Reed responds "I thought I'd take you to what I consider to be the very heart of the Universe, Joanna." On the very next page, readers discover Mr. Fantastic was talking about his wife Susan Storm, the famous Invisible Woman. The team gets straight to business dealing with a message from the planet Sypre - but the discussion between Reed and Joanna highlights exactly how he feels about his wife. Unfortunately it is a sentiment he rarely repeats.
Mr. Fantastic can clearly tell others how he feels about his wife, but has great difficulty talking to his wife directly. One of Reed's biggest flaws is his tendency to keep secrets. He's done this in nearly every crossover event, but most recently Fantastic Four: Reckoning War, in which he did not immediately inform Sue that he would die in three days due to absorbing Watcher knowledge. He was of course able to tell other members of his team, but not Sue. Reed failed to tell Sue anything about his impending doom, and while he admittedly did it out of a desire to protect her and spare her harm, it shows he has a hard time trusting the one person who he ought to trust more than anyone.
Reed Richards, for all his genius, finds it very difficult to relate to other people on a personal level. Modern writers often give Reed a very clipped and clinical way of speaking, even to his own family members. The power couple of the Fantastic Four truly love each other - they just find it very difficult to express that love in words.