I overhead people talking at work saying that too much of unprotected sex with your part is not good especially when pregnant?

Generally no problem: Sex is safe if done with one's monogamous spouse and if there are no sexually transmitted diseases nor any pregnancy complications (such as premature labor). As long as it is comfortable enough for both people, one can have sex throughout her pregnancy. Having intercourse and orgasms is fine as long as the pregnancy is going well. It is also important psychologically for both people.