She could be hungry.
If she is awake & hasn't eaten in 3 hrs, pick her up quietly, change her diaper, keep lights dim, be quiet, feed her, burp her & put her back to bed.
Try some white noise in the room.
You could do a nightlight behind her dresser so she has some very dim light.
Make sure she isn't teething (my son started at 4 months). If so, you can rub Baby Orajel on her gums at this point.
When I would feed my son for the last time at night (right before we went to bed at 11, I would do a "dream feed: p/u, make sure diaper was dry - if not, change it then give a bottle or nipple if breast feeding while they are still "asleep"....that would buy me 3-5 hrs at night).
Also, if I held the baby after feeding and they fell asleep in my arms, I would put the baby down w/i 10-15 mins for an easy transition.
I swaddled my baby until 5 1/2 months (that cut down on the moving & waking themselves up thing) but at this age she's probably too old.
If you do go in, just try in & rub her back.
Tell hubby not to worry about it since you're the one going in & trying o help her get back to sleep. Try to get out of bed quietly w/o moving the bed & tell him to stay cozy in bed & sleep.
Hang in there . Try what I said and this stage won't last long. None of the stages do, they are just hard to get through.