Shiv weaponises her vulnerability to victimise herself to force Tom into forgiving her [1][2] + doesn't respect his boundaries [3][4] when he needs space from her.

1. In 1.10 Shiv comes clean to Tom on their wedding night about her cheating on him, AFTER their marriage (despite Tom asking her beforehand and giving her a chance then). Shiv weaponises her vulnerability into forcing Tom to forgive her, bringing up how when they met she was a "mess" and in a "very bad place" and how she needs him and also tries to gaslight Tom about their relationship never being monogamous. He forgives her because he's in a difficult position (divorce on the same night as marriage?? She didn't give him an out to call off the wedding beforehand and waited until after he was secured), he loves her, and he's forced to sympathise and accept things.

2. Shiv only apologises to Tom when she sees how cold he's being with her in 4.8. There's real danger he's actually done with the relationship. The kicked dog isn't returning to heel. She apologises. He doesn't accept it (you don't have to accept an apology, especially if you're still upset and someone is tryna force an apology on you because THEY feel bad and want to alleviate their guilt and return things to something that THEY'RE comfortable with). She uses the fact that her dad just died, which doesn't change the fact that everything he said in the prior fight was true. Their relationship had been shit for ages prior to Logan's death, therefore Logan's death doesn't excuse the rest of the relationship, and he's still immovable. Damn, he's always comforted and folded to her before, he's not doing that right now. Shit. Bring out the heavy. I'm pregnant and it's yours! The ultimate card to reel him back. He wanted a baby right? But he doesn't even believe her now... Why should he care anyway? How much has she ever cared about him?

3. In 4.7 Tom walks away from Shiv and goes to the balcony, needing space, telling Shiv he's tired. She doesn't respect this need for space and corners him on the balcony, literally not allowing him any reprieve, and actively mocks him for being exhausted, pressing and pressing him until he snaps, despite the fact he didn't even want to fight in the first place. He needed space and wasn't allowed to have it.

4. Tom is exhausted and stressed out of his mind in 4.8 with his job (something that means the world to him and yet also something Shiv has never taken seriously - and how could she understand the importance it holds for him when she's a nepo baby). He asks Shiv to talk about this another time and that he can't do this right now. She doesn't respect his request and presses her needs above his and takes him aside again and isolates him, and then acts surprised and offended when he doesn't respond how she wants him to. Ironically if she had actually respected him asking to talk another time when he wasn't so stressed, she might have gotten the results she wanted: Tom back in her pocket.