It's not an easy thing. Over years it's gotten easier for me, and I've had a combination of therapy and meds, as well as a very (very, very) patient partner. Some of it is creating new connections to things. So say every time you watched a movie your ex was mean, of course it would be hard to sit down and watch a movie with someone. Getting through movies and enjoying them with your new bf would help change that, but it's really hard at first.
Lots of grounding early on, reminding myself where I was and who I was actually with. Deep breathing techniques to help with anxiety. It's a matter of finding what helps you. (If you're interested the Fort library has pages on grounding and distractions that you can look through.)
A big thing is to make sure that you're even ready to have a relationship. I wasn't ready at first, and the first relationship I had was hard going at the beginning. (Because of my trauma and his sheer confusion about what was going on) I'm very blunt, so being very honest and talking about what I could helped. I couldn't have my hands held a certain way, and so I didn't give details but told him that because of old stuff it freaked me out, could he not do that? idk works for me, doesn't work for everyone I know.
I wish you luck in your new relationship. Also, if you're interested you're welcome to sign up for the members only forums to discuss things like this that are the aftermath of abuse.
"You're only given one little spark of madness. You mustn't lose it." -- Robin Williams
"Don't be afraid of the shadows, that only means there's a light nearby." -- Evanscence
"Let me hear your war cry!" ( roar lol) -- In This Moment
"So when you’re feeling crazy, and things fall apart, listen to your head, Remember who you are." -- Three Days Grace
"But I am not really worried, I am not overly concerned. You try to tell yourself the things you tell yourself to make yourself forget." -- Counting Crows
"Our brains are sick, but that's ok!"
"Peace will win and fear will lose."
"And I will say that we should take a moment and hold it, and keep it frozen and know that life has a hopeful undertone."
"It ain't the speakers that bump hearts, it's our hearts that make the beat!" -- Twenty Øne Piløts