boyfriend dated ex for 7 years

i've been dating my current boyfriend for 6 months and everything's going smoothly except when it comes to his ex who was his first everything (first gf, kiss, etc.). this is his only ex and after her, he waited 4 years before he started dating me.

issues began to come up when i caught him in several lies regarding her (where she went to college, whether he saw her after they broke up, etc.). i realize that i may have been the cause of this as i talked about her a bit more than usual. but it wasn't because i was jealous; it truly was out of curiosity.

so what i can't figure out is why he lied (i never overreacted when he talked about her... even when he told me their intimate details)... i'm not mad about the content of the lies, i'm mad about the fact that he lied to me... is it because he still has feelings for her? do people just never truly get over their ex, especially if it was for 7 years? and these questions are getting in the way of our relationship

but he's always assuring me that he loves me so much more than he loved her. and that we have something they never did. and that i'm much smarter, nicer, cuter, blah blah. but are those just empty words?

any advice as to how to deal with this issue? he gets super exasperated whenever i ask him why he lied about those things.....

My Boyfriend was with his EX for 7 years + and also has two children with her.
He will probably always care for her. 7 Years is a long time especially if she was his first everything. But that's ok if he still cares for her and if he says he loves you then i would believe him (although i think 6 months is a little early to say the 'L' word, but everyone is different)

As for the lying, maybe he was a little scared that you were jealous and wanted to know everything. That is something that you will need to ask him, he might have a reasonable explanation for it, if he doesn't then you deal with then. I wouldn't make a big deal about unless he is hiding something.