The 39-year-old models' friends say he is her number one confidante and her relationship is complicated, reported People magazine.
"It's complicated. Their relationship is hard to define. This has been a difficult time. Her inner circle of people she trusts is getting smaller and smaller and he is her number one confidante," a source said.
Klum and Seal announced the end of their marriage in January after seven years together and she has previously said that she was enjoying life as a single woman and did not have any plans to marry again.