I can think of 3 approaches to this problem
A) you have your significant other use Apple Watch Family Plan and manage your Apple Watch from their iPhone. You get fewer features because your Apple Watch will not have full access to your Significant other's iPhone. Or you might not have an SO. This is also more expensive than the typical $10 per month when you can pair your Apple Watch to your existing iPhone phone number.
B) If your iPhone supports Dual SIMs (physical SIM and eSIM), then you can get a personal cellular contract from a carrier that BOTH supports the eSIM and supports the Apple Watch. Again, more expensive as you have 2 full cellular contracts (granted your company if paying for one of them).
C) You use the Apple Watch as if it was a GPS only Apple Watch. That is to say, to not activate the cellular radio. A GPS only Apple Watch can do Everything the Cellular model can do AS LONG AS your iPhone is nearby, where nearby is generally somewhere in the same moderately sized home. The Cellular model allows you to leave your iPhone at home while you go for a walk, run, bike ride, otherwise, you get the same functionality.
