According to Ashkenazi practice, immersion on any night should ideally take place after nightfall, tzeit hakochavim. (Sephardi practice on Friday night is to immerse after sunset but before tzeit hakochavim.) We suggest that you check your local times and contact the mikveh to see if they could allow you to immerse after tzeit hakochavim.
If that is too difficult to work out with them, you may immerse earlier, so long as your immersion is after sunset, shekiah. In that case, you should avoid seeing your husband at home until tzeit hakochavim.
Shabbat shalom!