Hmm, I just saw your earlier question that seems to relate to this one. If I am reading all this correctly, I think it's a combination of the terminology and the status of development of ancestral lines that is the root of the problem. Someone who was married to your mother is going to show up as a "connection" because your mother has a relationship to both of you. That's how the term is used here. Similarly, you would also have a connection to any wife of your biological father.
I think the reason you are not seeing more connections on either of your biological parents' side is that neither of their ancestries have not been developed very far. It looks as if both lines only go as far as their parents, and your father's wife has no other connections showing. It'll take a little time, but the way to increase the connection count through your biological parents would be to research their ancestry farther back, and if you're interested, looking at siblings of your direct ancestors as well.