40 in two weeks 😩

I’m 40 in two weeks. I have been TTC for 9 years on & off. I had a miscarriage with a previous partner and I’ve been trying ever since. It was my desperation of wanting a baby that made my last relationship end after 9 years of being together. I have been with my current partner for 4 years and we have been trying for the last 3 years. I just wanted a healthy child with a good man. I feel lots of guilt though as we both have children from our first marriages. To be clear my boys are 20 & 18 both born premature due to preeclampsia when I was very young with my very first & only husband. I struggled when we split up and he has not really played a part in their lives.

My partner has only been married once his children are 4 & 6. When we meet his little girl was 18 months this made my desire even stronger. I feel like I should be great full for the amazing children we already have and let the soul I desire make another wanting mum happy. Is it just because I’m approaching 40 that I feel like this? Is it natural to desire baby’s when your fertility is rapidly declining?