The 41-year-old singer told the Daily Mirror that his medical student fiancée provided a pillar of strength after his elder brother Andrew died of kidney cancer in December 2012.
"Everything changed when I lost my brother," Peter told the newspaper. "All my worst fears came out and I was a mess for so long.
Peter and Emily had been dating for two months when Andrew died
"If you say 'commitment issues' it sounds like it's from previous relationships," he added. "But my phobia came from losing him because I didn't want to lose someone again. That threw me into turmoil.
Peter Andre sets up charity in memory of his beloved brother
"But the genius Emily has made me so much better. What helped is that while I'm an emotional thinker she is a logical thinker. Honestly I don't think I could have got through it without Emily. I would have gone into my own shell."
Peter and his brother Andrew in 2012
In the two years since Andrew's death Peter and Emily have got engaged and welcomed their first child together, but the father-of-three says the grief is still with him.
Peter Andre opens up about coping with his brother's death
"It doesn't change," he said. "You still feel rubbish. The hole doesn't go but time does smooth the edges. I had some counselling and it helped a lot. You get angry in therapy. You think they don't know how it feels but my doctor was amazing."