Boyfriend doesn't want to have sex.

My S/O and I have been together for over a year and used to have sex about once a month, sometimes more, sometimes less. 
​Lately we haven't had it at all, like going on 3 months. He says he "doesn't want the stress of a possible pregnancy because he is already stressing enough about getting prepared for college," but I am on the pill, and have been for a long time.
​We have always had difficulty using condoms because he seems to lose his etection when he puts them on, but he has never finished inside of me, and I am very good about taking my pill. 
​Do you think he is honestly just worried about me getting pregnant or do you think there is another reason?