Simon made it clear right at the beginning of your little agreement that there is and will be no romantic relationship between you two, only a purely physical one.
The silence next to him in the Humvee was soothing, better than the painful truth he kept putting in your head when you tried to get even a little closer to him than on an emotional level.
Simon and you had been arguing again, he knew you would come crawling back, you always do, sooner or later, but before it comes to that, you give him always silent treatment.
"I like the way you kiss me," he murmurs, one hand on the steering wheel while he draws almost pitiful circles on the inside of your thigh with the thumb of his other hand, looking at the dark street.
"I can tell you missed me, maybe you should start using that pretty mouth of yours to talk to me again," his voice is low, dripping with exhaustion from the short mission your Captain Price has sent you on - gathering Intel and returning to base.
He gives enough to make you stay, but not enough to satisfy you. He's not trying to be romantic, he’ll keep you at a distance just so you don't get attached to him.