Warn hubby that the post pregnancy hormones are uncontrollable. Therefore, you can't control what comes out of your mouth if MIL upsets you If they insist on being there, just excuse yourself and close yourself into your room or babies room and when people try to enter, tell them you are trying to nurse and need privacy to get baby to latch and for you both to get the hang of it.
I like this post! Pregnancy hormones are definitely uncontrollable and unpredictable! Maybe DH should talk to other dads to get a better idea of what to expect. I'd only have the in-laws over if they are willing to cook and clean all the time. You need the bonding time and rest time with your newborn!