Is my nikah valid if I do not have intercourse every four months?

I just found out from website that husband to have sexual intercourse with his wife every four months otherwise automatic divorce occurs. After Rukhsati my husband did not have sexual intercourse for about a year or even more. Then when we did it there were other problems. Then we went through doctors for conceiving and we did have tests done. We found out later that he could not ejaculate. Then did IVf and had a baby. Then again he did not have any sexual intercourse for about 2 years roughly. Now recently every now and then he asks me for sexual intercourse sometimes we do it and sometimes i refuse. But we never keep in mind that it has to be done every four months.

We may do it more than after four months sometimes. My husband does not have much sexual desire as well. ( thats what I think) I am just fearing that we do not have much sexual intercourse every 3 to 4 months so does it constitute automatic divorce? We do not keep a track how often we do it but its really less not much so there can be gap of more than 3-4 months. He does not know about it and neither did I about doing every three to four months. When we do IvF its mainly due to male factor. His sperm quality is low and had been taking medications for that. And now not taking any medications. We are thinking to do another IvF for second baby, its hard for us to conceive naturally. Is our Nikkah Valid if we do not have much sexual Intercourse?( every 3 to 4 months) Jazak Allah khair