I slept with an ex on february 13th and then i slept with a friend of mine on february 22nd i found out shortly after that i was pregnant i was told i conceived/ovulated february 19th is my ex the father or could my friend be the father?

Because ovulation does not occur at the same exact time each month, and these encounters were so close together, it would be very difficult to determine. Your best bet would be to do paternity testing. Transvaginal ultrasounds are good at determining due dates, but confirmation over time is needed, and dates can be off by 5plus days.

Statistically ovulation on the 19th would support Feb 22 as the father, however, genetic (DNA) testing may be required to be certain.

Consider genetic testing after delivery to be certain of paternity.

After 9 weeks of pregnancy your blood and the blood of putative fathers could be tested to ascertain paternity. Visit this site for info and talk to your obstetrician for getting the test, Pre-natal Paternity testing: https://americanpregnancy.org/paternity-tests/non-invasive-prenatal-paternity-test/

Thats why they have DNA tests to determine the genetic profile of the child. You will have to wait at least 7 or more weeks to do the test. A non invasive test is best. A cheek swab DNA from the possible father and a small blood sample from the mother is the most reliable test with a 99% PROBABILTY.