Why are guys so sensitive before a relationship?

It seems that guys are great before the relationship and half way through...what is up with that?

Because before thee relationship their trying to impress you and show you what their like. Most guys will keep this up when ur with them as their girl, but others wont becasue they have you and dont need to prove nothing else toyou.

My boyfriend never changed. He still is just the same as he was before. A true gentlemen. I love it!

Yeah my boyfriends still the same to. I love how the majority of guyz get judged on the minority of low life guys out their.
Not all guys are the same, they dont all cheat, they dont all change. Infact some get better as time keeps going !

People put up a front until your gaurd is down. Some people are just fake. Lucky for me, I knew exactly who and what my boyfriend was when I met him, becuase that's who he acted like, was himself. He never pretended to be someone else, and all this time later, I haven't had any nasty surprises. I've just discovered things about him that only I know, like how sweet he can be!

Well why dont guys just be sennsitive throughout the whole relationship

Lols My first bf was really sweet and loving through most of our 3 month relationship but then during the break up was when he let down the fake walls he had and let me see what he tended to be like =P As for my bf now *it's a long distance relationship since he lives in Mexico =(* he was very funny, sweet and loving when I met him and he's only gotten better the longer I've known him =) But then we've both helped eachother through a couple broken hearts, people dieing and countless other things ^_^ Not every guy changes for the worst and some *a very few I'll grant you but there are some* don't ever stop being that loving, sensitive, fantastic guy you fell for lols

I dont know if i agree with that i mean maybe its just some guys because that hasnt really happened to me yet..i mean and if it does...whatever things happen people change..move on...right?

The only thing that has changed after two years is that Marcus farts in the bed and pulls the covers over my head whereas at the beginning he would never emit any bodily gases in front of me, lmao.
He doesn't stop trying, he's just more comfortable with me now.
Knowing he can be himself around me is worth more than him being on his best behaviour all the time.

I agree with Gem.
Thats how my boyfriend is. lol. He would have never done that at the beginning of our relationship either.
He is still just the sweet, caring, loving guy that I fell in love with though.

Im single at the moment.
but every single time i like a guy
i sorta give it away without saying anything
they always act soooo kind and as if they want to get to know you more
but i swear as soon as they find out by another person that you like them
they change from one person to another.