Swiss obviously no-one else knows what it's like to be on the inside of another couple's relationship BUT it usually takes 2 to make or break it. It is very unlikely to be your fault alone. I would hazard a guess he said it to hurt you. Try to keep it together enough to get through the day each day and worry about the big picture when you've had some time to mentally start dealing with it.
As a slightly related aside, my hormones/being on the pill caused MASSIVE issues between my DH & I in the first couple of years of our relationship. It broke us up.briefly, as I became a horrendous bitchiness with PMT. Genuinely, I lost the plot each month. Pg does strange things to your hormones. Thankfully for my sanity/marriage, I am ok when pg (although have my moments) but DH knows it will pass, because of our past. He often has to be very, very tolerant/patient, far more than I am with him. We do have some big rows but we have to suck it up after and apologise.
Hopefully Swiss a bit of time and space to get some perspective would help your DP twig the same sort of thing??! Perhaps some time with Relate or similar could help you both? hugs