Newbie and need advice

Hi. I'm Ted, 18 female.

I grew up in an abusive home and learned a lot of manipulative behaviors. My fiance and I have been together 4 years now and just moved in together about a month ago. I tend to say manipulative thing on accident and not realize it but when he points it out it completely destroys me because I love him and I don't want to treat him or anyone like I was treated growing up.

Lately he's been having doubts about us being together in the long run and even said he can see signs of us ending soon but he doesn't want us to end.

I'm hoping if I can help myself with the toxic behavior I've learned it may ease the feelings he's been having. I also struggle with opening up to him about my feelings.

Any advice?