Antonia, You've made a big decision and it's for a good reason. You need to be healthy and live life without pain. You have all of your feline girls depending on you too! And they will be your constant support afterwards, as well.
Please remember that it's normal to feel anxiety around surgery. And it's also understandable that you feel extra sad about losing your partner at times like these. But like so many other women - many of whom still have a 'partner', but get little in the way of emotional support from them - ultimately, we have to get through these things on our own terms.
I know you realise all this - but just wanted to let you know that i understand how you must be feeling.
I am thinking of you, and sending huge waves of support and strength to you.
I know how much love and motivation to keep going that I get from my beautiful dogs, so I'm hoping that you can get just as much from your lovely girls. Pet them and feel their warmth and love for you... they will always calm you down.