If you are SP Page Builder (by JoomShaper) user, you will notice that the lastest version 2.0 doesn't have 'Add Container' option and all your ROW will be in fullwidth.

This issue can be solved using custom css, insert below css lines in your custom.css (or whatever you are using) file.

.sp-fix-row-container {
margin-right: auto;
margin-left: auto;
padding-left: 15px;
padding-right: 15px;
}
@media (min-width: 768px) {
.sp-fix-row-container {
width: 750px;
}
}
@media (min-width: 992px) {
.sp-fix-row-container {
width: 970px;
}
}
@media (min-width: 1200px) {
.sp-fix-row-container {
width: 1170px;
}
}

Now you can use 'sp-fix-row-container' class wherever you don't want fullwidth at SP Page Builder as shown below.