30M I need help regarding my marriage with 34F

I'm a 30-year-old man, married to my 34-year-old wife. We've been together for several years and have 5-year-old twin daughters together. She also has an 11-year-old son from a previous relationship, and we all live together in a four-room rental apartment.

When we first met, she was more confident and had better self-esteem. Since the pregnancy, her weight has increased (now around 120kg), and she struggles with insecurity and self-doubt. She often says she’s working on losing weight, managing stress, and giving me more personal space, but it’s difficult for her. Despite her efforts, she always falls back into the same patterns—feeling anxious, fearing I will cheat, and needing constant reassurance.

Her ex, the father of her son, cheated on her multiple times and gaslighted her, which has left deep scars. She often fears I will do the same, even though I’ve never given her a reason to doubt me. If I want to go anywhere where she doesn’t know the people, especially other women, she panics and assumes the worst.

She needs constant closeness and gets upset if I choose to play video games instead of spending time with her. I need my own space, but because of her past, she associates "alone time" with something negative. She is often exhausted and spends her evenings mindlessly scrolling on her phone, while I prefer to game or do other things. She doesn’t handle stress well, gets upset easily, and when she’s angry, she puts up a wall—when in reality, she just wants comfort. She constantly fears that I’ll leave her and overthinks everything.

Last night, I wanted to go to a work party for once, and she lost it—accused me of choosing my job over our family, yelled at me, and wouldn’t let me help her. She even asked if I was wearing my wedding ring at the event.

I fell for the person she showed me in the beginning but feel like the glimpses of that person are less and less. Otherwise she is helpful, very kind and warm.

I’ve been thinking about divorce, but I don’t know how to take that step. I’m worried about finances and, most importantly, the kids. Has anyone been in a similar situation? How do you move forward in a way that’s as smooth as possible for everyone involved?