Hi,
Malachy Lynam and Catherine Donlon (as spelt on record) were married in the RC church at Moyvore (which is a village between Ballymore in Co. Westmeath and Ballymahon in Co. Longford) on 26th May 1835, witnesses were Mary Sheridan and William Sheridan.
The priest is not recorded, nor are the father's forenames.
A Catherine Lynam has a 1892 death record index for the Ballymahon district Volume 3 Page 20 (which included Ballymore and Raheen areas of Westmeath) and it gives her approx. birth year as 1817. This may or may not be your Catherine Donlon but the birth year is within reason of your Malachy born 1805.