We are sorry to hear of your situation.
The obligation to immerse in the mikveh is in order to allow physical contact between a husband and wife. If the husband is away for an extended period of time, the wife need not immerse until he returns.
If there is a reasonable chance that he will be released, you may continue to immerse. However, there is no obligation to do so, and it would not be considered a lack of bitachon if you do not immerse regularly until he is released. If there is little chance of him being released earlier than scheduled, we advise against immersing regularly until he is released.
If it will be possible for you to visit him in jail, you should immerse in preparation for the visits. This is certainly true for conjugal visits, and even for a regular visit so you do not need to keep the harchakot. If visits are unpredictable, you could do a hefsek taharah and count shivah neki'im each cycle, and then immerse only if and when a visit is scheduled.
It is not considered a brachah l'vatalah when a married woman who is completing the taharah process makes a bracha upon immersion , even if her husband is away.
Please feel free to get back to us with any further questions.
B'Hatzlacha!