Exactly.
We don't know the extent to how much he liked her, as in we don't know how much romantic feelings there were. And besides, it's not like he wasn't making out and fooling around with Petra earlier. He probably could have gotten further with her if he weren't as passive. Plus he was with Dizi a two or three days right before she came into the house.
I will say this, with the way Anna was all over Ivo, it makes me think that she really wanted someone to fuck her. Maybe she wanted Phil to fuck her but he wouldn't or maybe wasn't comfortable? It's hard to say. Anna clearly showed that she's not a shy girl seeing as how she got fully naked the first time she came into the house and let Phil cum in her mouth after a good BJ. I think she was looking for more than what Phil was able to provide and she wound up getting it from Ivo. All this is hard to say for accurate, but I think the bottom line is this, as long as Phil isn't upset then it is obvious that everything is OK.