Am I entitled to money in a bank account that my husband opened and deposited money into after our marriage if we get divorced?

If you live in a community property state, community property is property acquired during marriage.  Community property also includes income during marriage.  Each spouse has a one half interest in the community property.

Separate property is property acquired before marriage or after the marriage ends.  Separate property also includes income before marriage or after the marriage ends.  A spouse has no claim to the other spouse's separate property.

Since the bank account was opened during marriage and funds were deposited into the account during marriage, if the money deposited into the account was income earned during marriage, the bank account is community property and you would have a one half interest  in it.

If the money deposited into the bank account was income earned before marriage by your husband, the bank account would be your husband's separate property and you would not have a claim to it.

If the money deposited into the bank account was income earned before marriage and income earned during marriage, and those funds were comingled, there is a rebuttable presumption that the comingled account is community property and you would have a claim as to one half of the funds in the account unless your husband is able to rebut the presumption by establishing which funds were separate property and which funds were community property.  Your claim would then be for one half of  the community property funds in the account.  You would not have any claim for the funds in the account that are your husband's separate property.

If you don't live in a community property state, other rules may be applicable.