Hi,
It all depends on the satisfaction of your partner during the intercourse. Most of the time it is perceived erectile dysfunction when actually none of the partner has any issue with the erection. So please clarify with your partner if she actually has an issue with your erection. If she has, then only go for treatment with a psychiatrist, else stay calm because none of the medicine or treatment for it is 100% free of adverse effects.
Next Steps
introspect and consult your partner