From Quora:

My boyfriend is sad depressed because we can't see each other always, what can I say to him?

Tell him to get better and the rest should sort itself out. Maybe say something like this:

“Get the heck out of your head bucko. Enjoy the time we can be together. Instead of thinking about how we are apart and how sad that makes you, think about how you can make our next time together unforgettable, and do that for every time we will be together, and don’t think you will get a pass when we get married. Then you’ll have to come up with something every morning.

“And if you really do have so much free time, go take a course and make something more of yourself so that you are more attractive to me. Go to the gym and get fit. Learn to play a musical instrument and write me songs. Write me letters. Study the great letter writers and try to outdo them.

“Maybe take on something bigger than yourself. Make sure no one in your community is going to bed hungry tonight, or that the seniors who can’t get out don’t have to be so alone, or that the single moms can have an afternoon to get their hair done.

“There is literally a world of good you could do other than pine about your time with me. Go do some of that. Maybe start with making your bed every morning (if he doesn’t yet) and bringing order to your space so that any time I might stop by I would be surprised and delighted just to be there.

“Then work your way out from there.

“Maybe start with this book: Twelve Rules for Life.

“or watch this:

Jim Rohn: For more than 40 years, Jim Rohn honed his craft like a skilled artist—helping people the world over sculpt life strategies that expanded their imagination of what is possible. Those who had the privilege of hearing him speak can attest to the elegance and common sense of his material. It is no coincidence, then, that he is still widely regarded as one of the most influential thinkers of our time, and thought of by many as a national treasure. My summary of this talk is here.

“or this:

How to discover your "why" in difficult times

What has the coronavirus pandemic taught us about ourselves and our relationships? In a deeply personal and wide-ranging conversation, leadership expert Simon Sinek shares his own experience caring for his mental health as the world shut down. He discusses why we need to nurture friendships (in both good times and bad), explains why anyone can be a leader -- and reveals the secret to discovering your "why" in life.

“In other words, get your head out of your ass and into the world. At least you'll be useful. At the very least, you will be more attractive to me. At the very very least, you'll be thankful for the time you get with me instead of pining about the time that, were the world somehow otherwise, you might have had.”