It’s funny how on MN everyone always rants about how cruel it is to have an only child…until the woman is older and then the consensus is that it’s even more cruel and selfish to have a child when you are over 40…
I had my DS aged almost 43. Very similar situation to you in that I met my DH late in life.
I can live with not being a Granny, or being a granny who is too old to play football (!). My own parents were dead when I was in my thirties anyway, neither of age-related illness. Shit happens. The fear in this place of having a life that is not utterly conventional (2.4 NT kids, all done by age 30, 4 grandparents round the corner to help) is laughable.
We never used contraception again after DS was born. I’m 50 now, nothing happened, but we had IVF for DS so not massively surprised. I think I am a bit relived that I did not have the worry about whether a second child might have additional needs but I know enough younger Mums of additional needs kids to have worried about that at any age pregnancy.
If you are asking would you be U to have another baby over 45, that is a personal decision for you and only you and DH can decide based on your health, lifestyle and plans for the future. If you are asking whether not actively TTC and just leaving it to fate is a good idea I’d say no- try properly if you want another child. All or nothing.
If you truly are ambivalent then I’d say don’t do it, just focus on the positives of being a family of 3, of which there are many.
Good luck whatever you decide.