<human>: I'm m/24, she is f/24.
We have been going out for 4 years.
We are best friends, never fight.  I love her.
I have noticed recently that we haven't been as intimate and I discussed this with her.  We attempted to make more time for each other but it hasn't seemed to have worked.  I started to get nervous as she has never acted this way with me.  We have discussed marriage, babies, everything.

She has cheated on me.  I know because I found out via the usual means, looking on facebook etc.  I know I shouldn't have, but I really felt I had to as when we have tried to discuss the issue of our relationship she hasn't been forth coming (again, very odd as we are extrmeley open to each other).  I haven't told her that I know.

I don't know if it is, she has just fallen out of love with me or not.  That is fine, but it is the cheating I am finding it hard to deal with.  I can't think straight and I am numb.  I want to break up with her (or at the very least confront her).  There are other issues such as being very close to each others families, vacations that have already been arranged and so on.

I found out yesterday, should I confront her tonight?  I'm not angry (surpisingly) I just want to know the truth and then end it.

I know this is probably a highly common post, I apologise.  I just don't know what the heck to do.

Here is what I think I will do.  I'll drive over to her house later tonight and literally just say that I know what has happened and I just want to know the truth so we can figure out what is going to happen between "us".  It's not going to be dramatic, I don't want a fight or tears.  Heck, I would love to still be friends.  I just need to let her know that I know.

Jesus, I am rambling.  Any advice would be very helpful dudes.  Thanks.

Provide a brief overview of the text.
<bot>: I know my gf of 4 years has cheated on me, I think she wants out of the relationship.  What do I do?