Can a heart murmur that hasn't given you any problems make it harmful to have ?

My bf whom i live with hasn't had for me or showed a desire in abt 5 weeks. I'm trying to narrow down reasons. He told me once that he has a heart murmur, but he has played football for many years. I think that would exert more energy than . We have been together for 10 months and this is not the 1st time this drought has occured.