Lying bf. Need some advice PLEASE

So my boyfriend lied to me about his age. It turns out he's 10 years older than me & not 4. I know age shouldn't matter but my problem here is that we've been together for 3 months and he never told me until now when I happened to see his ID & was able to ask him about his birthdate. What would you guys do in my situation were for 3 months the guy you love lied to you?