Fighting shame and returning to prayer after a past mistake

As-salamu alaykum wa rahmatullah, I hope everyone’s in good health. I’m writing this kind of anonymously, because I really need someone to talk to-it’s been hard. A few months back, I fell into something haram with a guy I met online, on a chat platform. We didn’t know each other well, and things moved way too fast the first time we talked. This went on and off for about two months. We stopped completely, but I couldn’t get him out of my head because of the attachment that formed. Just to give some background, I’ve had some really painful experiences from childhood that left me with trauma, and I used masturbation to cope. When I met this guy earlier this year, I was super stressed with work, and the little comfort I got from him pulled me in, and I fell back into masturbating with him as a way to soothe myself. I regret it so deeply; it’s been eating at my soul for months. I feel so unclean and disgusted with myself. He isn’t my husband, not committed to me, and probably never truly cared-I’ll never know. I never sent him any pictures, and we didn’t talk after that, until recently when he popped back into that chat group and I reached out, wanting answers and hoping he’d care again. We talked in a haram way, but I felt nothing except lust, and it made me feel so low that I even stopped praying for a few days because the shame and guilt were crushing me. I spent the last three months begging Allah to give me strength, promising I’d never return to that sin (and I didn’t, he was the only one I got this kind of attachment to), and yet the moment I saw him again, I caved. I’m lost and don’t know what to do. I need help, and I’m praying someone can talk to me because this shame and guilt are killing me inside. I left that chat group and want to leave that platform for good, since that’s the only way he can reach me-otherwise, he’s just a stranger online with no way to contact me, and he’d be gone forever. Please, I need advice. Jazakum Allahu khayran.