Having a kid really killed it for me. I was very active before fatherhood. Hopefully things will change for the better in the next few months.
I don't sleep well because I tend to my kid a couple times a night and have a hard time falling back asleep. This causes me to not only go to bed later than I'd like, but also have broken sleep. I'd wager that I get an average of 2 hours less sleep every day since becoming a father. This DESTROYS my motivation to do anything in the morning except ingesting caffeine and going to work.
When I go home from work, I have to pick up my kid and watch her alone for a few hours. I've tried to lift weights, take her to Jiu Jitsu with me, etc, but she just cries a lot and gets into things. This kills any kind of joy I usually get from exercising, so I basically stopped for now.
To stick with it, pick an activity that you like to do. I feel a lot of people really don't like going to gyms to begin with. They like the results they get, but don't enjoy the act of doing stuff like running or using an exercise machine (I don't anyway), so they stop after a while. Most people think that doing "gym stuff" is what they need to do to get into shape, because it dominates our society so much. There are gyms all over the place with TV/radio ads, and infomercials running all the time marketing the newest fitness gadget, supplement, or routine. I've stuck with Jiu Jitsu for over 10 years because I actually enjoy it.
Sometimes obstacles get in the way. For me its been fatherhood, a work schedule that isn't conductive to attending Jiu Jitsu classes, lack of transportation, and lack of funds. These have all caused me to take breaks from exercise. Its always very hard for me to start up again once conditions improve, but once I start again the momentum picks up quickly.
Another interesting side effect of doing activities you like is it starts to influence other aspects of your life. I started eating healthier because I wanted to get better at Jiu Jitsu, whereas when I was going to the gym to lift weights I didn't care if I ate some nasty fast food lunch. I didn't care as much about getting better at weight lifting or running as I did about Jiu Jitsu.
Basically, if you have SSH access to a machine and Python is installed on the endpoint, you can set up a "VPN" over SSH. To me, this is much easier to set up. You can get by most of the time by having a vanilla Linux installation on a cheap VPS without any additional work.