Can't have sex with my boyfriend anymore.
Why is that?
I'm not attracted to him physically, I don't want to sound shallow but no women would want a guy who is already going bald.
It is kind of mean to blame not wanting your bf because of them going bald. There are plenty of other things to be attracted to aside from just physical looks.
I rather let him sleep on the couch than break up with him.
If you feel this way than it may be better for you to not be in a relationship with them. Nobody is forcing you to be with a specific person, so this may be the best way to go about it.