The 38-year-old, who has 11-month-old daughter Luna with Teigen, said he has been at his wife’s side at every step, as part of her recovery.
Teigen opened up about her mental health after giving birth in a moving open letter for Glamour magazine, writing: “Postpartum does not discriminate. I couldn’t control it.”
Speaking to PEOPLE, Legend said on Wednesday 15 March: “For me as a husband, it was my job to do the best I could to support her and understand what she was going through and do whatever I could do to help her.
“I feel like that’s the least I could do.”
Advising other dads in similar situations, Legend added: “As a man you don’t know internally what it feels like.
“You should read about it and understand what it is and really just be there to help. You need to be present and you need to be compassionate.”
He said everyone is learning as they continue their journey into parenthood and people should try to “figure it out together”.
The dad-of-one also said he was “glad” Teigen wrote about her experiences in a “powerful” letter to show other women they’re not alone.
In her open letter, Teigen wrote about the support she had received from Legend.
“John would sleep on the couch with me, sometimes four nights in a row,” she wrote. “I started keeping robes and comfy clothes in the pantry so I wouldn’t have to go upstairs when John went to work.
“There was a lot of spontaneous crying. He’s exactly as compassionate, patient, loving and understanding as he seems.”
For information and support:
Mind: A mental health charity there to make sure no one has to face a mental health problem alone. Call: 0300 123 3393.
Pandas Foundation: Charity to support and advise any parent who is experiencing a perinatal mental illness. Call: 0843 28 98 401.
Mothers for Mothers: A postnatal depression support group with information and peer advice. Call: 0117 975 6006.
PNI: A website run by women who have suffered from postnatal illnesses to share personal experiences and offer support.