Etiam in longinquitate sentio amorem nostrum fortiorem fieri in dies. Triginta quinque dies a tuo adventu absunt et septuaginta septem antequam una manebimus in aeternum, mi care.
Remarks about the translation
Mi care --> mea cara (if feminine)
Bridge by Lili: "Even in the distance, I feel that our love strengthens (gets stronger and stronger) day by day. (we are)35 days away from your coming and 77 days away from staying together forever, my dear."
Hm... Sorry, I didn't understand this part of the English bridge at start. I have been thinking more over the English bridge and have noticed it could be interpreted in both ways:
"35 days away from your coming and 77 days away from staying together forever"
1. You came 35 days ago...etc.
2. You will come in 35 days...
But the 1st option has no sense in the vicinity of of these "77 days from staying together"... Moreover Lilly already specyfied it in the post above...
So, you're right! "Antequam"! And with future tense I think.