There should be the option of the MC having very little prior sexual experience prior to the mission. Right now it feels like the MC is somewhat a huge slut getting ready for a mission that involves a lot of sex.
Step 1: tick off the promiscuous kink (duh).
Step 2: first boyfriend - unavoidable, no virgins for you (probably dev's decision, and an understandable one)
Step 3: teen relationships - 0 is available
Step 4: Surval/gap year - 0 is available
Step 5: kink vignettes - only 1 is unavoidable and can be turned into a short one-night stand
Step 6: serious relationships in uni - 0 is available
Step 7: casual realtionships in uni - 3 or 4 is minimum, all can be customised as one-night stands. Moreover, you can click the option which will lead to Agent just sucking them off, no vaginal.
Step 8: realtionships during intelligence career - 0 is available across all years
Step 9: uni professors/station chief/embassy intern/etc. - all avoidable.
Conclusion: with the exception of Agent's first love, to whom she presumably loses her virginity, Agent can have 4-5 one night stands while in university and
zero sex afterwards. Little player's input is required - just consistent role-playing. The guys she's going to sleep with in Scotland may very well be her partners #6, 7 and 8 respectively
in her entire life, and #3 and 4 whom she's giving access to her vagina, with #1 being her
first love. And she may be up to 30-yo up to that point.
If you wish for a complete virgin, say it bluntly. Otherwise - what is your concern?
Addendum: ticking the bisexual kink allows you to limit the amount of cocks being inside her to 1. One. The first one. You'll need to click "reload" for some time in order to make all one-night stands female, but that won't take you long. How can you have less experience (exclusively with men, though) than this?