Hi there ~
I understand your concerns. Metoprolol
do not have any effect on sperm morphology. I do not think you need to be worried about that. However if your husband is having problems with getting your pregnant it is a matter of concern. I hope you are sexually active and your own gynecological health is normal. Firstly you might need to consult an psychiatrist
to find out if your husband is having any difficulties with libido or have other mental health concerns like depression. Otherwise, a very common problem of erectile dysfunction
and / or premature ejaculation
might be the causative factor and it can be easily treated with medications available during this time. The class of medication is called phosphodiesterase 5 inhibitors (PDE5Inh) selective serotonin reuptake inhibitors and it also helps with decreased libido which is a result of depression if you are going through one. I advise you to consult with a qualified psychiatrist who might be able to help in this regard. I hope this helps.
Take care and have a lovely day!