Well I had a catheter twice. The posts in this conversation talk about self catheterization. Which can make living with occasional retention very manageable.
https://community.prostatecanceruk.org/posts/t22995-Escaping-the-Catheter
Whether to have treatment for the cancer? Bare in mind I know nothing about your situation, and am in no way medically qualified. I'm going to say "leave it". My argument is that about half the male population of your age has got about this level of cancer and for 70% of those it will never be a problem. So treating you now will give you unpleasant side effects for something which may never be a problem.
This YouTube video is from a credible source. It is quite interesting for people with marginal diagnosis.
https://youtu.be/yNzQ_sLGIuA
I'm glad Lyn has chipped in because you need to hear a range of arguments and opinions. Some members might suggest go for an aggressive treatment right now, and their opinions are just as likely to be as right as what I'm proposing.