She lied to him for basically no reason and had the equivalent of vampire foreplay with Damon (of course that wasn't really her fault since she didn't know). Elena lies sometimes for the stupidest of reasons (i.e. "You just looked so happy"). So I don't think he was too mean to her. He just gave her a scolding and then forgave her.

I know all of u will say no ge wasn't he has a right to be mad, maybe he does but the way he said "you lied to me Elena" makes you feel like she done something so horriable/bad, so what if she kept something from him or lied like "saint" Stefan pointed out didn't he LIE to her about being WHO/WHAT he really is in S1?? didn't he LIE/kept the whole Elena is Katherine "look a like" in S1??didn't he LIE/kept from Elena when he was drinking human blood again in S1?? didn't he LIE/kept from here the FACT he was a ripper and the FACT he KILLED all the original counsel family back in 1864?

I generally think he was pushing her too much.
His faith that "I couldn't do it, but you will, you'll become my improved version for your own sake" was basically stupid. He meant well, but all these celebrating, "you did it" despite of her being sick of hunger made her feel guilty. She pushed her so hard in the direction she wasn't able to go that she couldn't be honest with him about what she wants & needs and turned to Damon for help.
Of course Stefan was freakin' jealous,but the only person who should be mad at was himself - if he wasn't so blind & stubborn Elena wouldn't go to Damon, wouldn't feed on him, wouldn't lie about it.
Personally I'm extermaly happy about the turn of events ^^

I totally agree with @Epicurean. :)

Stefan, of all people, has no right to judge when someone's lying. He has been lying about his true nature, about his blood problem, his ripper past. And he wouldn't have understand if Elena told him about her problem, because he's in denial. He's always in denial.

Agree with @Talice

He was doing the right thing.

He was annoying her LOL :D

he the one who did this to elana i think he was annoying her so he need to give her space

Honestly Elena deserves neither Stefan or Damon.

agree with @PPPopopipop