Hi JoJo, I can certainly sympathize with your situation. You love both your Mum and your husband and when your Mum does not like your husband it makes it very difficult on you. You don't know who to side with, since you love them both.
If your husband is not abusing you in any way, your allegience should be to him.
If you can muster up the courage to tell your Mum how much it bothers you when they fight, and IF your MUM really loves you, she, being older than your husband, should not argue with him. It is easier to say, than to do...believe me, I know. But if your husband is a good man and if you love him and want to stay married, you will be better off telling your Mum not to argue with him.
If your husband is childish and deliberately picks fights with your Mum, then he needs help from a therapist to find out why he does that.
If your Mum continues to want to say and do things that irritate your husband, then she needs to stop coddling her daughter and find a more interesting hobby.
I do not know enough of the facts. All I know is you are tired of their bickering. You are really the only one who can stop their fighting. Tell them their behavior is making you sick, ill, depressed. If they continue, then you have to realize that neither one really cares about your feelings. They care about themselves. You then need to find yourself a good therapist to help you. Good Luck.