The website I like to use is priberam.pt. It may be a bit challenging because it is all in Portuguese, but at least this will offer you more practice with the language. :) I must admit that it does not explicitly mention the corresponding prepositions very often. For example, for «depender» https://www.priberam.pt/dlpo/depender, you can tell from the «Esta palavra em blogues [This word in blogs]» section that «de» is the preposition that follows, but «contar» does not have this section. This dictionary, though, is good for idioms/common phrases, as you can see all of the different phrases in which one can see the word «par» https://www.priberam.pt/dlpo/par, for example. Sorry if this was not of much use.
The post by Istriano on this page seems like a good guide to the sounds of "de" and "te":
So, while "de" can have that "dje" sound, it isn't typically used in this position.