Spend as much time as you can with each other in person or by phone {even when you have some mins off at work, also}. Share all the good things you enjoy, love about each other. {as others smartly suggested}. I'm glad he's a good person/father to you.
Prayer, good thoughts directed to a ill person [even very ill] can help [there are genuine studies that have already been done several year ago- i heard an actual lecture on this matter given at one of the most prestigous hospitals in NYC].