I had sex wit ex april22 and conceive date is may8 is it a strong possibility it's my ex or husband

IMPOSSIBLE to say with such scant information.

Conception dates are always just a guess (unless you had sex only once).
You will never know for sure unless you have DNA testing done after the baby is born.

Yes there is a strong chance it is, that date would fall right in line with the given conception date.

So after child is born, time for a DNA test.