Richard, I'm sorry you are going through it.
I'd like to tell you something for you to feel better but I can't.
I agree with what has been said about getting moré knowledge about yourself and caring about you before being with this or another partner.

Said that, you didn't do anything bad according to your experience. You simply falled in love and give love. Now, you have experience and know better than giving love is great but you have to keep a little of this love for yourself.