Before he wrote The Talk, Jeph had a plan for the future and ending of the comic, in which The Talk cleared the way for Faye and Marten to get together. The Talk, and the realisation that he now wanted to keep the comic running as it was now his main source of income, changed all that, so that he now lets the story develop as it seems to want to (in his mind); this is explained in the Afterword of Volume 2.
I suspect that the remark about there being no chance of happiness for Marten was more that he couldn't see it coming from the way things stand, with a memory of the feeling that if Marten did get finally settled that comic would have to end. In fact this is no longer true, of course, as there are now so many other characters; the comic could quite naturally shift to developing their stories instead, maybe with a happy Marten dispensing wisdom in the background.