I haven't been on relationships for ages, but I did want to post that it has been 1 year and 1 week since I found out that XP had been having an affair - after 2 weeks he decided he wanted to leave.
For those still in the early days it will get easier, you will become stronger, you will be able to think about it without wanting to burst into tears. You will get there. Ride through all the emotions, it will come in waves.
Take care of yourself and your children (if you have them), and let your friends and family take care of you :)