Thinking about how Dr. Grant is very likely apprehensive to get into relationships, whether they be romantic or platonic or anything of the like, and as such he likes to keep most people at an arm's length. He'll drown himself in his work just to keep himself away from people, spending hours upon hours working to the point of exhaustion because he'd much rather be left to his own devices than interact with anyone.
But, at the very same time, he's so touch starved and craves to be loved in any and every way a person can be loved. How he wants to be able to freely go out for lunch or dinner with a few friends and laugh about anything and everything. How he wants to wind down after a long day with a partner, eating a warm dinner and conversing softly and taking care of one another. How he wants to come up behind a partner a kiss them softly on the shoulder, to sway with them as music plays in the background of whatever setting they're in.
How, all in all, he just wants to form a connection with someone that's irreplaceable. But- it's as though he doesn't feel like he's worthy of such a thing, and so as much as he dreams and desires a strong relationship and connection with someone, he's too scared to do it because, deep down, he knows his distant personality will get in the way and he'll end up pushing said person away. He's scared of so many things, all of which can be refuted, but if anything that scares him more.
He just wants to think he's unlovable. Call it pitiful, if you will, but it's what he genuinely thinks.