......... Just, what? That's not even how it was presented in Warcraft 3. Obviously, he still had feelings for her, but his intentions after being released were to prove to both Tyrande and Malfurion that the demons had no control over him and that while he still struggled with making great choices, he had the best intentions as far as what side he was working for. When the two of them found him and wouldn't believe him, he figured out that he was on his own for good -- no family, no Tyrande, nothing.
The incident with them in Lordaeron was simply a nice postscript that wrapped up their story: the Malfurion and Tyrande perhaps understood him slightly better, and Illidan got to demonstrate his intentions.
Once in Outland, the only woman that consistently occupied his thoughts was Maiev Shadowsong, and that was to make sure she didn't find him and lop his head off.