They were both heartbroken after that, but Catelynn went to an especially dark place -- she began contemplating suicide. She made the decision to go back to that treatment center in Arizona, and Tyler fully supported her.
She spent six weeks there, then came home -- and just a couple of weeks later, she told Tyler she wanted to go back for another six weeks so she could work on some of the trauma she'd experienced.
A lot of things happened after that, but the gist of it was that Tyler didn't understand why Catelynn had to leave her family for six more weeks in another state when she could try therapy or even inpatient treatment in their area where they could visit her, and Catelynn was completely unwilling to discuss her choice -- she was going back to Arizona, and that was that.
Tyler began getting extremely frustrated by everything, and that got even worse when Cate came back six weeks later and refused to go to therapy with him, or to even do exercises his personal therapist suggested to help them get back to a good place.
Too Little, Too Late?
Finally she tried to compromise by suggesting a marriage retreat in Arizona (for real), and he went, but it didn't do much good. Just before they returned home, he told her he wanted a separation -- just a month or so where they lived apart
Right around that time, she got pregnant.