Do you know of Beck and JMJ having a falling out over a woman? This is supposedly the reason why JMJ left the band.
I am really not an expert on Beck’s personal life but I did some reasoning while I brushed my teeth. I don’t think so, honestly. Beck married his wife in 2003 I guess and his first child was born around 2003 or 2004. Beck rearranged his band with the release of Modern Guilt - that was 2008. So I don’t think that there was a woman involved because Beck was (still is) married and I had the impression that he just wanted to try something new with a new band. I honestly do not know anything about a woman involved.
Now JMJ and Beck reunite for the concerts he’s doing later this month (if I understood JMJ’s comments correctly on the stewoo.net boards). Hope this helps :)