Soo...

I had a miscarriage before and I just recently found out I’m pregnant again doctor says he don’t know what caused just a nature thing but since I’m pregnant again I just want to be extremely careful as I was cramping in my first and also cramping in this but I’m still extremely early so that’s to be expected no bleeding but I’m just alittle hesitant about sex and I want to make everything is okay first before and my fiancé is acting ugly saying sex can’t harm anything and how he wants some am I wrong for being careful?