I know what you mean. I think it is important to realize that we just can't have everything we want. I know you know that already, but sometimes I have to tell myself that in the same tone I tell my daughter that I'm not actually going to pay for her to go see Selina Gomez in concert and while I understand that it means the whole world to her, I'm simply not paying for it.
By the same token, I can't imagine paying another private school tuition, college tuition, medical bills, etc. not to mention dividing my time up even more and spending less with the kids I already have. So I talk to myself in my adult voice. I can't have a baby just because I want it. Lol.
You have both my empathy and my support. :)