Looking on the internet deeply has found these results:

It's a relief he is the most popular phrase on the web.

It's a relief that he 1495 results on the web	It's a relief he 159,200 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
It's really a relief that she acted like a prosecutor. It's such a relief that things are finally better at meade. It's such a relief... that he didn't get a chance to see you and Park Na Young. Anyway, it's a relief that Ae Jung's scandal was covered by Dokgo Jin's. It's a relief that you have come back. It's a relief that the commoner gangster Geum Jan Di is my girlfriend. It's such a relief that you've returned safely. It's a relief to hear that he has been found.	It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

It's a relief that he

1495 results on the web

It's a relief he

159,200 results on the web

More popular!

It's really a relief that she acted like a prosecutor.
It's such a relief that things are finally better at meade.
It's such a relief... that he didn't get a chance to see you and Park Na Young.
Anyway, it's a relief that Ae Jung's scandal was covered by Dokgo Jin's.
It's a relief that you have come back.
It's a relief that the commoner gangster Geum Jan Di is my girlfriend.
It's such a relief that you've returned safely.
It's a relief to hear that he has been found.

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.