<human>: My boyfriend has recently moved in with me and my two roommates. Both of them are girls, but I don't really know them - we mostly stay in our rooms, and don't communicate more than necessary.  We're definitely not friends. Basically, one day he commented that he thought one of these girls was was attractive, and now he won't kiss me in front of her! 

I first noticed this a few days ago when I got home and both of them were in the kitchen, each preparing their own lunch. I said hi to her and moved in to kiss him, but he didn't reciprocate. Granted he was busy cooking, but when he noticed my disappointed look he moved closer and gave me a peck in the forehead.

I've been paying attention ever since, and he deliberately avoids being affectionate to me in front of this girl. I actually went as far as to ask him why, and he told me he is shy. However, that makes absolutely no sense because we  frequently kiss in public (like in the middle of the street, or while on public transportation). He also has no trouble kissing me in front of his parents and siblings, as well as in front of my family members, and friends. There has never been an instance where he had felt uncomfortable kissing me in front of anyone prior to this.

What do I do about this situation? Am I crazy for feeling insecure over such a small thing?

Could you distill the essence of the text into 1-3 sentences?
<bot>: my boyfriend commented on the attractiveness of our female room mate and has avoided being affectionate in front of me since then.