Questions on how to get a divorce

[cheatedon]

I have been married for almost 3years and recently found out in December that my husband had been cheating on me with a woman who had been in my presence several times! I dont know how long they were involved (because he is a liar ) but I suspect it may have been going on even before we were married. Anyhow, we have a host of other problems as well because he is not on my level intectually. Within the last couple of years I realized he could not read on a 1st grade level. We cannot even conversate because he perceive things differently that of a "normal" person. I have a B.S. in biology and I'm now working as a LPN. So its very difficult for us to communicate because there is a mental block between us. We have 2 children together, a house, and 4 vehicles. I want a divorce ASAP but do not know how to go about doing so. Can someone please lend advise on cost, how will infidelity play a role in may case, how long might this process take?