Gettin married next year and my PS library's lookin a little empty

What if you were engaged, but you and your partner decided not to get married anymore and instead live out your lives just like before. Can you still wear your engagement ring or is that strange and unheard of? 

He suffers from ptsd but I am not sure,since he doesnt want help, neither from me nor from anyone else. Months ago my boyfriend was in jail because he has avenged the death of his mother. I went to visit him regularly but he didn't want me to come, and refused my visits til I stopped going there. I was pregnant and extremely distressed about him and about us, and our kid. I was afraid me being sad and stressed would have hurt our baby. since he came back, right before the lockdown, his behavior started to change. At first he was happy about coming back, kissed and cuddled the baby, held me tight. After some time I noticed he would lose his temper quickly, insult me during discussions, said 'who knows with whom you did that baby' making me cry and leaving home for two days. And everyday is a nightmare, he behaves good and then he turns into the devil, hurts me with words ans answers sarcastically. He has always been a really good guy, protective, caring, provided for his family, couldn't wait to have our baby, used to kiss and touch my belly and talk to our baby while he was there. He always said 'my little one, I can't wait to hold you'. He was so good and pure hearted. Now he has turned into something else, and it scares me and makes me sleep all tensed up and worried. I'm afraid he will hurt us (he never tried to hurt us physically, but I am afraid of it). I want to protect our child from him, sorry to say it, I'm scared of him now. I'm sure it's pstd, he has all the  Symptoms but hw refuses to admit it, says I am tired of him because I found someone else, and want and excuse to leave him. It's not true, I just need help from someone who can help him, because at the moment I am so scared of him and cannot believe he is the guy with whom I fell in love with. He was not like this. Something in jail must have happened. He also said I did the baby with someone else how on earth? I was virgin and he knew that. Why is he hurting me on purpose?

I stopped working 19 years ago because I became disabled.  Needless to say I don't have much money.  Would it be so wrong to ask his family to pay?