Bulk Insert From Txt File Less Data Than Columns

Hi, I´m trying to bulk insert files that looks like this:

aaaa,bbb,dddd,
ccc,dfd,tghj,

each file can have up to 10 data fileds per line, and each file will have same number of data fileds in particular file, let´s say 3 like above. Second file could have let´s say 10 and that is maximum.

I read the file and insert data with fieldterminator in temp table from witch I insert data to other tables regarding some parameters inside.

Now problem is:
Msg 4832, Level 16, State 1, Line 1
Bulk load: An unexpected end of file was encountered in the data file.
Msg 7399, Level 16, State 1, Line 1
The OLE DB provider "BULK" for linked server "(null)" reported an error. The provider did not give any information about the error.
Msg 7330, Level 16, State 2, Line 1
Cannot fetch a row from OLE DB provider "BULK" for linked server "(null)".

That is because I´m trying to insert 3 fields of data in temporary table which is made of 10 columns (It have to be 10 because next file could have 10 fileds of data). If the temp table has same number of columns like text file has data fields than it works.

What is solution for this problem?
Can I bulk insert NULL in columns for which I don't have data?

I can also import each line of text file to one column (with delimiter inside) but than I don´t know how to insert that data to correct tables or even to one table but to seperate data fields to columns with fieldterminator which is , in this case.

I'm new to SQL and I would apriciate any help.
Thank you