Is there a full story behind this or just a picture?
Off the top of my head there could be multiple situations:
1) She is a sleeze and went into research after her boyfriend was deployed.
2) They are actually married but only for the extra benefits you received as a married soldier. He is OK with her doing whatever while he is away.
3) They are in a relationship and both parties are aware of what she is doing and are OK with it.
4) They are both in the research pictured.