what do you do when you live with a liar?

I have 3 children we have had to move 4 times this year because he is passing bad checks for our rent.. He is non stop lying ...I find no evidence of drugs or alcohol or gambling or other women . He always has money for myself and the kids such as going out to eat ,toys or the movies ..He has not held a job more than 2 months ...I know I should leave him but Im also pregnant ...