Hello. Welcome to hcm.
The symptoms which your boyfriend is facing occurs in males commonly. If the pregnancy
was unplanned,then men tend to get disturbed by the amount of responsibility that comes with it and tend to go under lot of stress
which is similar to women who get pregnant and tend to get stressed about pregnancy.
In men,it can be variety of symptoms including low sex drive. You need to have a talk with him about what is bothering him showing him that you are genuinely worried. If he is not interested,then both of you visiting a sex health psychologist
will help in understanding the cause of his behaviour.
All the best