how many children did he want?!
From the many books I've read about the Romanovs, I haven't seen an exact number given for how many children Alexander II wanted. But even so, he did have quite a few if you count the four with Ekaterina:
with Marie of Hesse-Darmstadt:
1. Nikolai b. 1843
2. Aleksandr III b. 1845
3. Vladimir b. 1847 (He married Miechen)
4. Aleksei b. 1850
5. Maria b. 1853 (She married Alfred, Duke of Edinburgh)
6. Sergei b. 1857 (He married Alix's sister Ella of Hesse)
7. Pavel b. 1860 (He was father to Maria and Dimitri)
With Ekaterina Dolgorukaya:
1. George b. 1872
2. Olga b. 1873
3. Boris b. 1876 (He died the same year)
4. Ekaterina b. 1878
So in total, Aleksandr II had eleven children. Not as many as George III of England (He and his wife Charlotte had FIFTEEN!) but that's still alot...