No. His willing things apart from Himself is not absolutely necessary because the goodness of God is perfect and can exist without other things inasmuch as no perfection can accrue to Him from them.
Yet it can be necessary by supposition, for supposing that He wills a thing, then He is unable not to will it, as His will cannot change.
God wills His own goodness necessarily, even as we will our own happiness necessarily.
But God wills things apart from Himself insofar as they are ordered to His own goodness as their end.
As the divine essence is necessary of itself, so is the divine will and the divine knowledge; but the divine knowledge has a necessary relation to the thing known; not the divine will to the thing willed. (The reason for this is that knowledge is of things as they exist in the knower; but the will is directed to things as they exist in themselves.)
Since then all other things have necessary existence inasmuch as they exist in God -- but no absolute necessity so as to be necessary in themselves, insofar as they exist in themselves -- it follows that God knows necessarily whatever He wills, but does not will necessarily whatever He wills.