Just because you're not in the same room (or state, or country) doesn't mean you can't go on a date. Rather than resorting to the same run-down every night (How was you day? How was work? I miss you.) find ways to make your time together exciting and ever-changing.
Try cooking the same recipe and "eating" together, or watching the same Netflix movie during a Skype chat. Crack open a bottle of champagne and have a tipsy heart-to-heart. Read to one another. Play Words With Friends or chess online. Send an interesting article you read that day and have a friendly debate about the issue. Schedule a special night together, and craft a Spotify playlist or send her a new dress to wear for your "date." In making the extra effort, you're not only keeping things fresh, you're also showing how invested you are in the relationship, which makes you both less likely to look for affection elsewhere.