Not sexually/Romantically attracted to me anymore

My SO just informed me that he doesn't know if he is sexually/romantically attracted to me anymore. We haven't been having any sex lately due to him being stressed out (he is leaving for training for MARSOC in less than 3 weeks which is his biggest dream) and I've started a new anti-depressant which just killed my sex drive. But I didn't really think anything about it until he told me this. We've been together for 2 1/2 years and have never had this problem before... how do I get him to want me sexually like he used to? What can I do to spice it back up especially when I have less then 3 weeks and then he is gone for 3 months? Please any advice would help!