You have to support Spencer with everything. I got the less than perfect ending the first time I played, but after reading comments on here (plus some helpful hints from Dyne Wulf himself) replayed it.
Normally I snoop when cleaning the bedroom after we first move in and find his guilty pleasure stress relief tennis ball. I also tell him not to quit school, but otherwise support him in his tennis dreams and tell him to keep working at DS since he loves it so much (and encourage him to strip all the way). This time I didn't snoop and didn't tell him not to quit school and got the perfect ending.