Introducing a 14 y.o. cat

My partner will be moving in with me. She has an 8 year old female and I have a 14 year old male who has never been around other cats and for that matter, has never even seen another cat. He is very meek and timid and I am so worried that this may not work out. I have researched introducing cats but cannot help but wonder if my 14 year old will be able to handle this major change in his life - not only a new cat but also another person in the household even though he spent a month with my partner and that did work out - he seems to like her very much and has accepted her (first time him liking a another person).
   
Please, I could use all the advice I can get. I am so worried about this.
   
Thank you very much.

HI from Ireland ,
   
Recently i had a similar situation . I have an elderly female cat and in a moment of madness i rescued a nine week old male tabby as a play mate and companion for my other cat .
   
At first she wouldnt even enter the room if she thought the kitten was in the room and if she did happen to be in the same room she would his ,spit and smack the kitten .
   
That as a few months ago and thankfully things have improved greatly .They are not the best of friends as the older cat is very set in her ways . However they live side by side without arguments .The even manage to share a rug in the evenings .
   
I suggest hand feeding them a tasty treat .Then both of them will associate having a nice treat while being beside each other .
   
I know this works as i just brought home a puppy and i share ham between two cats and puppy with lots of petting for both and words of praise .
   
Also at first supervise all of their meetings .Dont force them to be together as this doesent work .