Advice on what to do....

Im currently 26 weeks pregnant, im 23 my husband is 24... due to changes in hormones my sex appetite has increased. The problem is that a few months back my husband doesn’t have the same sex appetite. We talked but the only response he gave me was that he is tired most of the time. Im not sure if is because pregnancy, if im not in his interest anymore or if he has another woman. I tried to look for him in bed but I stopped due to the fact that everytime I tried he was not in the “ mood” for it...... im not sure what else to do.... help......