It’s a bad idea to date unsuitable partners in hopes they change. Dating someone whom yiu need to fix after only 6 months of dating is a waste of time honestly. If he needs fixing before it even starts then what’s the point.

I would take out of equation what happened in previous relationships and focus on what’s happening now. What’s happening now is you are in unhealthy relationship with unsuitable partner. I’d not recommend you waste another minute of your life on this

If you had unprotected sex, I’d also check for STDs right away.