After DS2 was born (who was unplanned - but an "happy accident" that DH accepted with no issues) he said he wanted no more children.
I wanted more - possibly 2 more, but definitely one more.
Our marriage was shaky, but I fell pg after a night of carelessness. I took the MAP, it didn't work, he wanted me to have a termination. I didn't. He eventually agreed to support me during the pregnancy. We nearly split up when I was 4 months pg. Managed to hold things together (just). He was distant during the pg, our relationship was dead in the water.
Yes DS3 was born and he loved him to bits. But he still "blamed" the pg on me, I'd engineered the situation etc etc.
BUT - it didn't fix our relationship. When DS3 was 9 months old we split up properly. At 29yrs old I looked on the positive side and thought "wow - I may actually get my 4th!!".
Nearly a year after we'd split up a couple of life changing events in DH's life, and a newer stronger me, miraculously we are back together (doesn't happen often in relationships that had gone as sour as ours had). We are very happy.
HOWEVER - I spent over a year thinking "there's a chance I may get a 4th". Now we're back together I know it's not going to happen. It hurts like hell. But you know what, I'd rather have my marriage back together and a fabulous relationship with DH and my 3 DC that I do have than try and risk the whole thing for a 4th baby,
DH knows my feelings - I've told him I'll have moments of great sadness until my mid 40's (so another 15yrs yet) - my mum desperately wanted a 3rd child - my dad didn't want one. She's still sad about it today (and I'm the youngest of the 2 she had), but she says the pain "lessened" when she hit the menopause and she realised her body was saying "time up").
If anything it hurts more now than it did when I was a single mum of 3, as the possibility of finding someone that I would want to have a 4th with was only a possibility. now I'm back living with a man who I know would make fabulous father of 4 - but that only wanted 2 (but ended up with 3).
Agree with those that say you need to look at the deeper issues surrounding your feelings on this.