David vs Goliath

For a long time now I have been playing against a person that is rated about 1800 Fide, I think.  That is my guess.  Maybe he would be rated more like 1850 but it is close to 1900.  Here are a few starting positions that occured while playing him.

What are good ways to combat any ideas white may have to win btw?

Next game...

and this game:

Any suggestions based on what I said?