After and Before Clauses

guys. I would like to ask whether a clause should always be in the past if it follows another clause starting with after in the past. For instance: After she read the note, she understands/understood the situation. Should we use understood here even if the person still understands it?

Another question Is it possible to use a clause in the present before a before-clause in the present to indicate that the person has started to do it and still does it. For instance: He loves me before he sees me.

If you want to describe the current situation, I would use since rather than after.

Since reading the note, she now understands the situation.

With before, it needs to be:

He loves me before having seen me, or

He loves me before he has seen me.