I am new here. Can someone point me in the right direction? Where to start first?

BW 51 (me)
WH 47 (husband) MLC
OW (I have no clue but need to find a way to find out)
17 together. Married 16 years.
Status of Marriage? I have no idea, but it is looking like he is going to leave

(Heelsdown is a horse riding term)