The actress divorced Black Crowes singer Chris Robinson in 2006 after six years. They have four-year-old son Ryder together.
However, she said they had remained good friends and she often checks out women with him when they visit bars.
She told Eve: "Chris and I are so cool. I'm really lucky. We share houses in New York. No matter what happens, Chris was my biggest love - we had this amazing son and we both love each other.
"It just didn't work out. Whoever ends up in my life has to know that Chris will be in my family forever. I look at women with Chris now. I can sit in a bar with him and we say, 'She's cute.'"
Hudson is believed to have reunited with ex-boyfriend Owen Wilson.
> Hudson admits she still loves ex