When to ask for divorce

Suoer long sorry...

I have been contemplating for awhile now and feel like it's the last resort now. I've tried everything and am tired of feeling like a last choice. He plays games like it's a part time job,never helps around the house, communication is not there and he gets mad or sad whenever I try to have an adult conversation. He legit acts like a toddler, tantrums and all when I ask for help. We haven't had sex in 11 weeks, and we never spend time together anymore. I have to beg him for attention. I want to feel loved and like he's interested in me. The other night I legit begged him to come upstairs bc I had a nightmare (pregnancy does that to me) and he did but basically made me feel like I was stupid and like it was my fault for watching the vlogger Bailey sarian before bed claiming it was giving me nightmares bc she was talking about true crime. We finally had a good conversation and I felt like we we were vibing again for the first time in months or even years and he pulled his phone out mid conversation!!!! I told him I felt like that was hurtful and rude and he gaslighted me saying I do it all the time and I was being sensitive but I literally don't.

Hr also has an ongoing flirtatious banter with his online friend and will spend hours talking to her. I've asked that he stop bc I feel it's disrespectful to our relationship but he won't. He says it's just friendship and he doesn't even know her bc they're online...but I told him it's emotional cheating and why can't he spend that much time invested in me and our son.

Our son told me the other day "I'm so mad at daddy because he won't play with me". He's 4 and feels how disconnected his daddy is. I just wanna give up. I can't do this alone anymore. I'm going to school till time for my masters, work full time and do all the household stuff myself. I've asked if he's depressed and suggested counseling, he won't. I'm in therapy already and they've suggested couples counseling but he won't.

I am afraid to leave bc his family is overbearing and has connection to lawyers and stuff. I'm terrified to lose my son and I want full custody bc I don't fully trust that his dad is capable of following through on things. In fact in sure he wouldn't. He was a stay at home dad for 3 years and our son needed speech therapy for a speech delay cause the whole time he was home he would be on video games instead of interaction with our kid.