Hi Nib, welcome
Great to see so many valuable replies here.
I'll try to be gentle but objective as well as I have a few things relevant to your situation.
My first long term girlfriend was not suitable for me- but I was in love with her and love makes you ignore the flaws. She had severe mental illness issues and I didnt think I did however many years later I found I had bipolar and other stuff. After 5 years in desperation to get to the bottom of why she left me 2 to 3 times a week I visited her psychiatrist. He told me "you are young and she is many year older, but she has many issues in life. You would be far better off to move on and find a lady with none of those issues."
This hurt me. I believed in terms of love she was a "one off". I'd never be able to love someone as much as her!. So I hung on and a further 2 years I realised- nothing will change, her DNA was set. I left her.
Twenty years later I drove past her house as I was working in the area and curiosity made me notice she was gardening. We had coffee and chatted. She told me she has a boyfriend and I found out he had the same issues with her as I did, indecision, verbal violence and so forth. I realised then that I did the right thing by leaving. More importantly, I'd fallen in love 3 more times, the last one is my now wife and she is adorable and much more compatible.
I'd like you to think about this man, that there is more to a suitable partner than handsomeness. That other features including - age, baggage and compatibility all make for long term lifelong partnership, not just good looks.
As for not knowing what he wants, by now at his age he should. For me it is unacceptable that he is robbing you of your young adulthood why he messes around with what he wants in a woman. If he is that undecisive then is it good that he enjoys the fruits of the relationship while he waits for his decision making to arrive?
So in the words of that doctor some 35 years ago that tried to give me advice that I ignored- perhaps you should be looking for love with someone that is more suited.
I know it is difficult to listen to these words but I'm being honest.
Finally, it is up to him to disassociate himself from his ex and her family. If he doesnt do it then he has a reason why he allows the contact to remain. If she is the mother of his child there is some need for contact but any more and it is hurting you then he should protect his relationship. Sorry but it is another reason to consider moving on.