"Normally I hate to talk about anything personal, but it would be a lie if I did not say it has been difficult," said Mathew, who was managing Beyonce's finances but is said to have gone wrong with them.
The decision to walk in opposite directions was mutual, reports thesun.co.uk.
"It was hard for me to let her go. It was hard for both of us to let each other go. And let's be clear on that. She didn't let me go, we both let each other go. That's a big difference," he added.
Mathew, 61, says ending of a very close relationship was painful but he looks at it in a positive way.