Jeremy, having met Theresa when he was only 23 (she was 28 at the time - note the emotionally significant ages and the vast difference in maturity between them) embodied the younger man looking up to the older woman dynamic. Theresa's career was firmly established and on the rise. Undoubtedly she taught him, supported him and was a crucial ingredient to Jeremy's success. Over the years however while Jeremy's career took off, Theresa's was flailing and she increasingly lost touch with reality as she saw conspiracies as reasons for her failed projects . Her despair and fears permeated Jeremy the way any close couple shares their pain but this situation was insidious because her mental problems went largely unchecked because she was an artist and a writer and they say and do wacky things and it's extremely difficult for people on the outside to know when there's a real problem. In this atmosphere Jeremy was the younger guy taking the lead from his older woman - whatever she said portrayed as reality was his reality. Their paranoia became a self-fulfilling prophecy - the more skeptical friends and family grew of their accusations, the more they felt misunderstood and even attacked by their surroundings and reinforced the belief that they could only trust each other. Jeremy's mother is quoted saying Jeremy was a loyal caretaker - how incredibly apt. That statement plus Jeremy, seemingly out of left field, accusing a colleague of trying to ruin Theresa's reputation all point to him as an impressionable guy so wrapped up in Theresa's perspective it became his and he was doing all that he could to protect her and ultimately them. He wasn't able to step out of the dynamic and see things differently than she did. In terms of his art and whether he was able to conceive of going on in life without her, she was his one worthwhile audience member and critic. His critique of the art world was growing as was her/their paranoia and the two of them became sealed as each others trustworthy muse and critic. In the end he couldn't go on without either. To the core, Jeremy was influenced by Theresa and until the end lived and died by her perspective. As his suicide note simply says, he wanted to be reunited with her. After all, the only adult life he knew was with her and in the last few years of their lives, insulating and endangering themselves in the 'us against them' cocoon they built.