Accidents are more prone to happen than not. Bruce knows this quite well, as he was involved the incidents that changed his life. The Hulk came from an accident, an accident that no on had been prepared for. An accident that had changed his life and how he interacted with others. Especially his perspective on relationships and whether or not he should be in one. Currently he was back in that kind of situation...the famous Tony Stark the object of his desire and the opposite. He knew how Tony felt about him, Tony never was one to hide things or tip toe around the subject. He made it blatantly obvious how he felt and what he wanted though he kept things slow, only because he knew Bruce couldn't handle any other.
Tony should know by now that what he is doing is dangerous. Playing so close to the monster that Bruce kept so well hidden behind the calm smile, and the brilliant conversations that ensued between the two of them. Bruce can't accept that Tony may love him, every part of him. It's too much to handle, too much to worry about. Too many variables to consider, none of this was rational. But then again, Tony Stark has never been one for rational thoughts or actions. The secreted kisses in the halls, the touches that lingered long after Bruce was alone. The amusing conversations they were able to have, and all the plans they had together. This had to end before someone got hurt, he wouldn't know what to do if Tony was hurt because of him. The Hulk was a monster, a part of himself that he liked to keep well hidden and the only way to do that was to stay out of situations just like this, to throw himself into work. No matter what Tony said he was still the monster, Bruce and the Hulk were one, they both caused destruction. If they were truly separate entities then shouldn't he be able to stop him, to keep him chained up and locked away.
He tried, every day was a continuous battle to keep the monster under lock and key. Holding him back, telling him no, trying to put reason to him only made it harder and harder. Hulk didn't understand the destruction he cause, the hate the Bruce had at himself because of it. Every day he fought against the Hulk, the more the strain pulled at him to just give in, to let go and let the monster have his way, to let him do whatever he wanted and fuck the consequences. Tony made it easier, he really did. Though Bruce didn't want to admit it, the strain was less when Tony was around him but at the same time he was playing with the fire and Bruce didn't want him to get burned. No matter how good it might feel. No matter how Tony made him feel just by being in the room, or the promises whispered in his ear in the dark that the Hulk wouldn't hurt Tony. It wasn't enough, it wasn't enough to make him trust himself...not completely. A problem he has always had, one that Tony never questioned, even when Bruce pulled away in the middle of a kiss, Tony understood and never pushed though Bruce knew he wanted to.
Which is why he couldn't leave, he loved spending time with the billionaire, genius, playboy, philanthropist. He loved the look he got when he was puzzled over something, the smile and excitement he showed when he figured it out. The sparkle in his eyes and the mischievous grin when he had something foolish and dangerous planned. The way his hair never sat the same way, it was always a mess of brown locks, soft and easy to run his fingers through. His soft voice when he explained parts of the arc reactor technology to Bruce, and told him about his past and anything else that popped into his mind. Another part of Tony that he adored. His brilliant mind, the way he phrased things, and the thoughts jumbled in there. He knew he could talk to Tony, that their conversations would never reach a dull point and that Tony would always have something to say even when Bruce couldn't think of anything. Overall he just loved Tony, every part of him, the arc reactor and all, which he knew was dangerous but he was starting not to care.