He blocked you because you kissed a girl... That's pretty stupid in my eyes, doesn't he like lesbians or something. Either way he shouldn't be childish about it, you kissed a girl, so what! It's not like you kissed a guy, now that would be just bad. Kissing a girl while being in a relationship in my eyes, doesn't bother me at all aslong as the girl loves me. Kissing a guy is a different case obviously.

In the end it all comes down to your boyfriend be slightly childish about this, you should try catch him and speak to him, if you can't do that get a friend or someone that you know or he knows that you can trust to ask him what's wrong.

Hope I've helped

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