Sam, it's perfectly normal. Semen is initially thick when ejaculated, but after a short amount of time becomes runny in consistency. No matter what you do, you'll never be able to hang on to all of it, and it won't affect your fertility at all.

However, as you have eben TTC for about 3.5 years, it would probably be a good idea to get some preliminary testing done on both of you if you haven't already (I note the laparoscopy) to make sure everything is OK.