"I do not want to deprive him of this."
Translation:אני לא רוצָה למנוע את זה ממנו.
למנוע אהבה ממני
is fine, but a little less natural. I'm not sure but I think you're right about the את - the object is not definite and therefore doesn't require את, and that makes the word order a little less flexible. That is consistent with ran_g's observation about the different prepositions: they convey the information and enable a more flexible word order.
The more natural scenario would be אֲנִי רוֹצֶה לִמְנוֹעַ מִשְׂחֲקֵי־מַחְשֵׁב מֵהַיְלָדִים שֶׁלִּי. In the other case the computer games would be deprived of your kids. The direct object indicates what someone does not get, after the preposition מן is indicated, who does not get something.