We co slept until about 18 months, then did first part of night in cot in own room and in with us from 2am wake up until just under 2, when I stopped bfing. She now sleeps beautifully in her own room with the occasional night with us if she's poorly (she's 2.3).
It is hard with a 12 week old, once they are bigger you can slip away when they are asleep to get your evening back. It's also easier to bf lying down once they are bigger.
To facilitate escapes I managed to slide her into the zip up sidecar crib when she was little, and pillow obstacles, something soft below the drop and monitor vigilance worked when she was bigger.
We also had a sleepyhead, though I think they stopped recommending them soon after.
I also didn't evict DH, instead made my edge of the bed safe (attached crib, then cot or bed rail), and I slept between them.
It also gets easier in terms of positioning, in a couple of months you'll feel more able to sleep in different positions without worrying. After 1 year when she was sturdier and more physically able we would sleep with her in the middle if we needed to.
For us, she woke multiple times a night until after 18 months no matter what, and we coslept so we didn't have to get out of bed all those times. If she'd slept through earlier we'd have moved her earlier. We did try a few times to check it wasn't the cosleeping causing the waking.