I will spare you my Afrikaans because it will bring tears to your eyes.
Kennith and I planned to have a child after being together for +7 years.
For me it was clear that I was going to give this child my surname, but as the pregnancy progressed I realised that this was really going to be a problem for Kennith and he knew that the decision lay with me, and was not going to pressure me, but I knew that it would really "kill" him - especially when we realised the baby was a boy (boys and men and inheritance and passing on and all that).
After much soul searching I went with Kennith's surname, and used my surname as a 3rd name.
By the time we had a second baby it became an issue for me, as now I wanted to have my kids with my name, but clearly we were now at a juncture that I could not go back on.
It really was a huge issue for me and led to many fights - but it was a bit of closing the stable door when the horse had already fled.
I felt angry for giving in the first time, but we also were having other problems in our relationship, so this was just another one.
But I also had to look and think if I had not "given in" back then, what would it have said about the permanance of our relationship, and would it have lasted further?
16 years on, we have 3 children and I have used the same formula on all 3.
Kennith and I are getting married in July of this year, I am not sure if I will take his surname or keep my own - but for me the decision I made +8 years ago still was a good one.
However there are moms who have fallen out with thier parnters and are now due to marry anew and it now becomes an issue. Or they sit with more than one child with different surnames, which is really not great.
For your partner to put the baby on his name - as an unmarried couple - you will both have to go to the Dep. of Home Affairs and both sign the form infront of an officer.
If you put the baby only on your name now, your partner can put the baby on his name later - only with your written permission and the cost of a name change. (I do not think he actually adopts the child legally, it is just a name change, but you need to check thi with someone as I might have forgotten the way it works.)
Once the baby is on your partners name, you will never be able to change it without his written permission - which I doubt he will give.
Whether the child has his surname or not, the rights that he has to that child do not change.
It is a heavy decision, so give it some thought, especially in the context of where you and your partner are going with your relationship and how this baby will impact on it.
I hope that helps and does not confuse you.