If you do not have 3.5 hours free tonight, find the next day or night when you do and mark it off for yourself. If that's more than a week out, maybe it's time to cancel something, mm? Parents may wish to make a deal in which one gets tonight off and the other gets a night next week; send your partner away with the kids to pizza & the movies or minature golf or something similarly time consuming.
First, take 20 minutes to clear the clutter out of the bathroom and the bedroom and any sight path between them so they're nice places to be.
Wash your hands.
Put on some very relaxing music.
Change out of your clothes into a robe.
Pour a nice big glass of water.
Drink the water while you locate a few books or magazines you've been thinking about reading. Get sucked into something for a chapter or an article.
Finish the water and pour a second glass.
Make a little treat for yourself to indulge in a little later. Perhaps a cheese plate or some bread & chocolate or a glass of sherry and seasoned nuts. Put it next to the bed.
Make sure the lighting and air circulation are pleasant & soothing.
Bath lovers, it's time for a really good soak; break out the bubbles or scented oils if you like. Shower fans, have a long one with some nice scrubby exfoliating soap or some similar treat.
When you come out all fresh and nice, retire to the bed to enjoy your treat and get lost in a book.
The rest of the world will do just fine without you for a while…