Okay, so I've been working with this guy, I'll call him Brian. Brian and I have been working together for about 6-8 months now. Well, at first we would just flirt at work; super harmless. Then he gave me his number, and then we hung out once. Then like a week later he tells me he has a girlfriend; who he's been with for like 2 years. With a couple months break; and when he told me this, they had just gotten back together after their break. Well, then we hung out again, and he was a little drunk but walked me to my car and we made out. It was amazing. He tells me to not "catch feelings". It's been a few months now, and since then I've spent the night at his house, I've met his family, his roommates. His sister (they're super close) tells me how much she likes me, and his brothers are super nice to me. He even introduced me to his parents (we went to their house and played beer pong). Well, his girlfriend, I'll call her Amy, has NO idea about what's been going on.
A few nights ago I stayed at his house and for the first time we cuddled and held hands... I feel like he's starting to care about me, in a different way. And of course I enjoy that but I feel TERRIBLE for Amy. She doesn't deserve this. She's leaving in mid-January for Army boot camp. I don't know what's going to happen once she leaves.
If he wasn't with her, he'd be completely perfect. Like I see myself sharing a life with him. I just don't know what to do.
HELP!

Let me see ? "she does not deserve this " but you have no problem, going out with him, making out with him, and snuggling with him ?

Of course when you are the girlfriend, I wonder who will be snugggling with him when you not there.

The right thing is not to see him and not to be with him.

You are the problem, you are doing this.

Agree!
Tell him how uncomfortable you feel, and good bye.
Do you want a guy who can't break up with a girlfriend before he gets a new one? Or, as in his case, tells you not to 'catch feelings' yet makes out with you and brings you into the family? UGH.