Regex to match email (not strict)

I would like to validate if an email address is entered by the user but I don't want to be too strict on it... So I came up with this....

My current if statement with regex:

if (preg_match('^/.+?@.+?\..+$/', $_POST["email"]))

However, I would not work for an email address with multiple periods...

For example:

testing@test.one.com

How can I allow multiple . or periods?