I'm on miralax (polyethylene glycol) and dolcolax by doctors. i want to have sec but will sex make me constipated? or are they not related?

It shouldn't: But, since we can influence our body's functioning greatly by what we believe - especially if we feel anxious about it (self-hypnosis), it is possible you can experience such a symptom. Ask a doctor, nurse, pharmacist, teacher, librarian to help you learn more about the different systems for digestion & sex until you believe there is no connection. Then, relaxed, you won't be constipated after sex.

Not related: Sex should not affect your constipation as there is no relation.