The 40-year-old stylist - famed for her work with Nicole Richie and Lindsay Lohan - split with Todd Shemarya, who masterminded her clothing range for shopping channel QVC and various endorsement deals, as she wants to work with her husband Roger Berman on future projects.
Todd, who has worked with Rachel since 2006, denied the split was acrimonious, adding he believed her to be a "very talented woman".
He said in an email to the New York Post: "We had a great time and accomplished a lot in this time frame.
"This year we came to a mutual agreement that we had pretty much accomplished everything we could together and it was time for us to separate. No drama. I think Rachel is a very talented woman and I wish her all success in her future; we just saw the future very differently."
Earlier this year Rachel had another change in her personal life with the welcoming of baby boy Skyler in March.
However, she admitted afterwards she was upset because she had always wanted a girl.
She said: "I always had this plan in my mind that I was gonna have this little baby girl. I found out I was having a boy, and I did cry for a week. Or two. Maybe even three."