Your boyfriend seems very distant to you and selfish, its not right there is a problem and you sure do not deserve to be treated like this. Have you had a mature adult talk together about the situation? It really could be anything. At his age i dont think a low libido is in the scene tho it may just be that as every male is different. He might have a lot of stress going on? How far in to your pregnancy are you? as being his first child may be freaking him out a bit ? With the sexually transmitted stuff that you have mentioned, it could be something to look up on, such as a health check up to see if it has affected him in any suspect could be self issues such as embarrassment? The first thing i would be doing is having a one on one adult talk. If that does not work you need to jump it up to the next step as in councilling? Talking to your health specialist ?