long distance

So my boyfriend and I of 5 years are doing amazing but in January I leave for school. This means that it will be the first time we have ever been apart for more than 2 weeks. I am going away to the east coast. We have said we will stay together and work it out. I come back in may and return to the east in sept. Now my question is, do I need to even ask/tell him that I don't want him sleeping around??? This has never been an issue before.