Caught my BF in a lie!! But now I feel horrible

My bf and I have been together for over 3 years. Last week Monday he told me he had to work so I believed him but I came home early and he was there and I asked why he was there then he said he got off then seen on his phone that he was with his buddy that day and asked him about it and he still said he worked so I started fighting with him because of the text then I find out he was lying because he bought me an engagement ring that day now I feel really bad because I spoiled the surprise he told me that he can't do anything without me finding out. Now he says he is going to wait to ask me to marry him because I found out. So stupid of me to be do mad on where he was but he's a bad lier!