Boyfriends weight

Hey guys, so my boyfriend and I have been together for 3 years. He used to participate in Tae Kwon Do 3 times a week but stopped around November time, therefore he is not doing the exercise he used to making him gain weight. He has explained to me that he is not comfortable with his weight, of course I have supported him and tried to comfort him and told him I love him regardless. But I was just wondering if there is anything I can actually do to help motivate him to lose the weight or just help him in general? We are going for runs every night.