I once read that over 50% of people quit an exercise/nutritional program for weight loss within 8 weeks.
One key issue is to establish a routine, which many fail to do. So, initially, yes there may be some perseverance.
That said, you also need to address the lifestyle issue. If your training is clashing with certain things in your life (work, social etc.)...then it isn't a good long-term solution. You need to establish a routine that fits into your daily schedule that you can enjoy.
What I have found to be a great motivational tool is keeping records. This could be in the form of numbers (weights lifted, distance ridden, body weight, waist measurement, body fat etc.). It could also be in the form of photo's (which are very motivating once you see your progress).
A question you can ask is "am I enjoying my workout routine?". If yes, then you can actually look forward to your training - and hence increase the chances of long-term application. However if you don't enjoy what you're doing, then try changing it around. For example, if you become bored after running for an hour, try some sprint work. If you don't like a particular machine, change to another exercise. Go outdoors rather than in a gym. There are always plenty of alternatives.
Personally speaking, prior to bodybuilding, I used to hate weight training. I never trained at any great level of intensity and as a result I became bored lifting the same weights week after week. It wasn't until I went into the weights room with a more competitive mindset - aiming to beat my previous performance EVERY time - that I became addicted to this form of training. Now I cannot wait to get into the gym each time and set new records.
Here are a couple of Q&A's I have available on Amino Z (as you can see...you're far from alone):
I am losing motivation in my 12 week challenge. I wish a fairy could jump out and make me skinny!
I just completed a BodyBlitz challenge and failed! I ate healthy and exercised but lost no weight at all. I want to try another...but can't get motivated.
What can I do to become motivated toward my health and fitness goals?
I lack motivation and find it hard to go into the gym. Can you help?
Hope this helps mate.