You can try something called Fading. It's where you put them in their own crib/bed and you use your voice to soothe them. Each night or every other night, you position yourself a bit further away. Read to them, sing softly or just talk comfortingly, but never pick them up. This usually should be started around the ages of four to six months and is a part of sleep training. It might take a bit longer since she is already so much older and use to the way things are. But if you stay strong and don't give in, you can teach her to self soothe with less crying.
Also, be ready for her to wake and cry during the night. Some will say let her cry, but you don't have to. You can go in, talk to her, readjust her position, but again, don't pick her up. Talk, sing, read, but slowly move back every once in a while.
@MiraRoss You're very welcome. I hope it works. Let me know if you try it and it helped any. I also hope your bf will understand it just takes some time for her to get use to something new.
I have to say that for everyone its different but you will need to make the choice earlier rather than later and work through the inevitable grumps, cried and complaints. If you don't kids work out very very quickly howe to manipulate parents. Be patient when she keeps coming back though but firm and consistent and expect set backs.
have the 1year old start sleeping on her own. use the ferber method if she cries. https://en.wikipedia.org/wiki/Ferber_method (not sure how it'll work on an older baby.)