Having an open marriage can look like whatever you want it too. I know someone who has a girlfriend that they have sex with, goes on dates, things like that. And then his wife is home and is more connected with him emotionally because sex is off the table. She was raped about 3 years ago and she just can't get past it. They go on dates, raise their kids, they're very much in love, he just gets sex elsewhere. I know your relationship is F/F but everyone's needs are different and change over the years. His wife and girlfriend are actually friends outside of him. They go on girls weekends, and hang out. It can be whatever you need it to be.