Get out a white clean rag.
Pour bleach on it.
Now observe the result.
Your boyfriend may have problems with his laundry.
You have a problem becasue you are with a hard headed stubborn man.
Relationships are full of rough roads.
If this is going to be his attitude towards you and life then you may want to clean out of him.
Try using white vinegar on sweat stains.
Sweat leaves behind a residue of salts.
Being salt they do not dissolve well with soap.
Wash the shirt in soap and add baking soda to the water.
Baking soda will soften the water by precipitating out the alkaline salts.
Then in the final rinse water add a cup of white vinegar which will dissolve the residue on fabrics.
You can treat the arm pit stains with white vinegar directly as a spot treatment before the wash also.
Just rinse out the vinegar before you add to the soap and soda water because you want to keep soda and vinegar separate as they neutralize each other.
For that white-white look you can buy Mrs.
This is an old fashioned trick.
A light blue dye is added to the rinse cycle.
The blue adheres to the fabric and neutralizes the yellow color.
The result is a bright white effect.
Wash whites with whites and only with whites is the rule.
Every time a color is washed a little bit of dye will leak out.
That transferrs onto other articles and makes a dingy look to lighter colors and to whites.
Do not use fabric softeners because these place a layer of wax on the clothes that will build up over time.
To remove the dingy look of wax softeners just add a cup of white vinegar to the final rinse cycle.
Do not store whites in the path of sunlight as this will cause yellowing over time.
Do not store whites in cardboard or wood without first lining the box because the acids in wood and cardboard can cause yellow spotting on the fabrics