I’m NOT even REMOTELY trying to sound qualified or competent enough to offer good advice, but I have lived a lot and am also in a long , established marriage. The kids are grown ,and we’re empty nesters. If I can offer one thought, it would be this ; Take a look at your wedding photo, and remember the girl you married . Look at yourself in the same photo. Father Time, circumstance, tragedy, life in general beats the hell out of a relationship. You both are the same people as the two in that photo, but just weather beaten by life. Try to take a step back, and re access your journey together, where you started from, and where you are right now, and what got you here to this point . You’ll very likely find answers that you never would have anticipated. Good luck to you both , sincerely.