Rue the day?

[summer_reine]

Dread to me implies that it will ruin the current time with him whereas rue seems more like a happy now but sad later term

 

[Voboy]

Dread to me implies that it will ruin the current time with him whereas rue seems more like a happy now but sad later term

Depends on how it's handled.

"Ruin" is a strong term. I think it's clear from what the OP has posted that her sorrow over the eventual separation is never all that far away from her. It's something she thinks about frequently enough that it darkens her current happiness occasionally, but leaves it intact most of the time. That's hardly "ruination," I would think.

"Angst over a future event" is what the OP says the aim is here, and that pretty much perfectly describes "dread" to me. At the end of the day we've given the OP options, but I disagree that rue the day is the best term.