Many of us have been there. You put on your favorite shirt and it’s too small. It’s not a sudden weight gain, it’s the shirt, you have the shrink. There are a couple of reason why this happens.
Some garments made from cloth constructed with cotton which involves many strands woven together and then it gets quite sciency. As fibers are spun into thread they get stretched and the hydrogen bonds that hold it all in place will get stressed. When you put this into a hot wash, the energy produced makes the stressed bonds relax and they return to their normal size, which is smaller.
There are shrink proof garments which is cotton, or other material include cross links which prevents the stresses occurring in the first place and therefore does not suffer the shrinkage.
If you buy clothing with synthetic materials then you will not have to worry about them shrinking. For example, polyester will not absorb as much water which means the shrinking is not so noticeable.
When you go out in his and hers shirts you both will want them to look there best, otherwise that great look you are both going after is going to be ruined. Take the advice here and make sure your tops are looking good and not the shrunk effect when heading out together. You also do not have to worry about ironing and this does not cause any kind of shrinking and going out in a wrinkled shirt is a no no.