Allah says in Quran ( And your Lord creates whatever He wills and chooses, no choice have they.) 28:68.
When the zygote is formed, it means that it was created by Allah, so, no one has the right to terminate the pregnancy. Your husband has no right to kill this embryo by abortion. You need to tell him that he should not object on the Wisdom and Mercy of Allah which created this embryo. No one knows what is the future of this child but Allah who created it.
Abortion is type of killing of a human being and it is a major sin and has a penalty called Diyah like the penalty of killing. The only case in which abortion can be allowed is when the life of the mother is in danger because f the pregnancy and there was no way to save the life of the mother but only by abortion.