Yes, it does make perfect sense. Especially to find out that when he 'bragged' about these things that you had a great part in developing and making them happen, he is taking all the credit. I think this is a part of how some WSs may need to build themselves up, because for whatever reasons they truly don't feel that they are successful/accomplished/admirable. To me, it goes hand in hand with the reason for many affairs, that being that the WS is trying to find ways to feel good.
I found out just recently that my H had told the OW that 'he' gave our daughter money for graduate school etc., as though he and he alone gifted DD with this when in actuality it was money that I made doing some consulting work that enabled us to be able to help DD with that expense. Made me grind my teeth!
That all said, I hope that you can reclaim your pride in what you have done and accomplished and not let his boorish comments to others affect your sense of success and feelings of pride.