How can I balance slightly erotic roleplay and story based roleplay?

I know this question makes me sound like a pervert but especially with the epidemic me and my girlfriend ended up unable to have much contact.(Not even calls since her roommates are always in the house and it would be really awkward with them.) As a result we have been exploring new avenues and in the end as we are both TTRPG fans we decided to run text based solo games for eachother where we could at least feel a bit close and flirty.

Now the problem is I am not particularly familiar with the concept of running games with erotic features and as a result I am not sure how to balance the NPC’s flirting as a substitute for our actual contact and actual story. Neither of us want the game to essentially be a glorified erotic roleplay. Now my question is how can I keep myself from including too much relationship stuff without fully avoiding them altogether.