You should enter your details into taxcalc.ie and look at the difference.
I tried using the figures you gave. The net income comes out a bit bigger than you have quoted, but you have not told us if either of you pay VHI, pension or other salary deduction, so I ignored that.
Your salary = 37,751
Your wifes salart = 25,028
According to taxcalc, your net income is 50,239 but if you were jointly assessed it would be 51,278.
AS I saw, these numbers are not exact, as there must be other salary deduction, but they should illustrate the advantage of joint assessment.