Sorry to hear about your relationship troubles.......
Just celebrated my 27th wedding anniv. yesterday! 29 years together in total. She doesn't even ride a bike! I have been an inveterate bike commuter for 20 + years.........We are happier and more in love now then when we met 29 years ago.........
Any kind of exercise is good for depression and anxiety (the real psych. kind) and also good for the lay meaning of being "down."
Communication is key to a long standing good relationship.........
And introspection and self-exploration can help find out why things didn't work out.....
Remember the only people we can change are ourselves.........took me a long time to learn that but it is amazing that changing yourself and your attitudes can actually affect those around you (you can often get the change you want from those around you).......
Ghandi: "Be the change you want"