First of all, you should acknowledge that your lover is staying away on a different place and that you cannot remain in contact with him or her all the time.
Make sure you spend as much time with your lover as possible through online chat, phone, skype or through emails.
You should also talk to your soul-mate and specify a time that you could spend together through phone or online chat. Internet has made it easy to stay in touch without spending much amount of money.
Always try to spend your vacations with your lover as it will help in giving strength to the relationship and both of you will not feel lonely while staying at different places.
You cannot travel frequently to visit your lover as it becomes difficult and costly as well. So try to utilise all other resources to stay in touch with your lover while staying at different locations.
Try to make every visit memorable which will make to both of you happy even when you get back to your place.
You should communicate with your soul-mate on regular basis as it will help in building a strong relationship and will not let both of you think about someone else.
Trust is the most important thing that either makes or breaks relationships. You both should have trust and faith in each other and try your best to maintain it.