Age gap between 2 married characters

Okay so I just started writing and want to write an age gap couple of 17 years but don't want it to look like a grooming thing so how could I got about writing they got together after the age of 18 and it's more of a developed into a relationship.

Characters are: John 50 runs with a MC that have a Sober bar his wife Eliza is behind the scenes with the bar and his life but they have been together 15 years now.. 5 dating and 10 married with few knowing that.

Eliza was on the street at 15 when her foster kicked her out for the last time she was on the street 6 months before meeting her adoptive father and through him met John who's kept her safe as well these last 20+ years of knowing each other

I actually figured out a way for it not to be so weird and will be keeping it quiet till I write it all out now

Thanks for the help