I think what most people here are saying is that parenting is not just about love. Love is the easy part!
The rest of it is about hard work, and logistics, and skill-building, and decision-making, and budgeting physical and emotional resources to make sure everyone has what they need.
It’s like saying, I have a full time job that I am so lucky to have and I really love. It is a calling, and a vocation. But it’s not quite like most people’s jobs - it involves working long hours, and I’m on-call every night and weekend and all of Christmas and all the other holidays, and it’s a role where there is a ton of responsibility and constant crises and not much opportunity to delegate, and I can’t ever resign or take a sabbatical or take a sick day or annual leave.
Given how meaningful that job is to me, though, should I maybe take on a second, full-time job, at the same time? And hope that, I dunno, it’ll be a bit easier? Or somehow there will be energetic economies of scale from having 2 jobs?
OP may wish to prioritise her existing child she does have, given that it’s unclear exactly what his needs will be, and they may be complex.
Adding a whole other dependent person (of any neurotype) to the family system will necessarily mean she has less time, attention, energy, money, patience etc to go around.
And when your DC has significant differences and challenges, you need do all you can to help them navigate the world. You can’t just halve the your resources without thinking carefully about the consequences.
Should a second child also have additional needs, the chances are greater that the whole family will be stressed and under-resourced.
(And bear in mind that it’s statistically likely that one or both parents have some health or functional challenges themselves - whether that’s anxiety or OCD or EDS or fibro or chronic fatigue or Chiari or any of the other things else loosely correlated with autism - so they be already be operating from a place of depletion)
It’s about trying to make sure everyone has enough of what they need. Not whether a person is loved or wanted.