This app was mentioned in 2 comments, with an average of 1.00 upvote
MySwimPro for iphone , or android.
It provides workout sets for Novice, Beginner, Intermediate, and Advanced swimmers. It also lets you track your progress and edit sets however you like. Its totally free - check it out
To your point about swimming alone, nothing will beat having a swim partner. But I'm working on MySwimPro to add features where you can share your progress with friends and do challenges etc. so it sort of helps with that.
First, what watch are you using?
Never used it...but this appears to have a Wear app and sync with Google Fit:
https://play.google.com/store/apps/details?id=com.myswimpro.android.app