TL, it seems to me that you're fine with them being together alone while you're nearby and somewhat involved in the date. Going to get food for the 3 of you, or "sitting poolside" while they're getting it on in a hotel room.
But while you're at work, you're not comfortable. So, it seems to me, you're not jealous she's with D, you're just envious of her having a good time while you're at work.
Are you envious of ANY fun she has when you're at work, or just sexy couple time?
OTOH, you did seem jealous she didnt jump up to leave the instant you said you were ready to go at the end of the night. Glad you both apologized for that incident.
BTW, he came 5 or 6 times that night? Damn!
He's a hottie.