i used to stay with my pils until my hub is totally dependent on his mother for everything. He is literally like a small boy towards his parents. Staying together has its pros and cons. If child care arrangement is an issue, mil definitely has her plus points there. However, you might be prepared to lose some privacy and intimacy time with your own family. 
We moved out after staying for 2 years and my mil comes over to help us with our children from Mon to Fri. Weekends are our own family time. I find the current arrangement is good as there are lesser possible conflicts with pils and I am to build up my little nest. Be courageous and talk to your hub on what you think.
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