Yes I know about choke option variants.
Now for Alison part it was encouraged by Ian that's why I also mentioned
If you read dialogues carefully there is clearly a difference between how Ian behaves and encourages Alison by saying
Now Alison saying I love you is disguised by how Ian behaved and encourages her to be vocal. That's why Ian didn't take it seriously and both didn't have any conversation about it afterwards.
While IanxLena was a different behavior. Ian didn't encouraged her or anything. Lena was the one who couldn't control her emotions and said it aloud.
There is difference between how both IanxAlison behave together during sex and how IanxLena behave together during sex.
Later IIRC Ian and Lena's dynamic is also somewhat like how Ian is with Alison but Lena avoid saying "I love you Ian!" specifically!
(I'm talking about how they(IanxLena) vocal they get with eachother later on).
The first part was encouraged.
i "What's that? You're loving it, aren't you?"
a "Yeah, I love it... I love having you inside me...!"
a "I love you, Ian!"
This was unwarranted. She couldn't keep her feelings in check. Followed by
a "I love you so much!"
Ian simply ignored Alison's words because he didn't care. Ian/Lena and Ian/Alison have a totally different dynamic. Even if he doesn't love Lena he still cares for her deeply; on the other hand, he just sees Alison as an outlet nothing more nothing less by default. Which will change according to our choices.
Like I said, you blurt it then you meant it one way or another. It seems we have come to an impasse. You see it as a burst of emotion during the intimate moment which means nothing after that moment. I see it as a lingering back thought that came out during the heat of the moment and it meant something.