what does it matter now? What's done is done? That's why you're supposed to wear condoms at all times and really use birth control as well as a back up. Too late to do anything about it now.
Thick white could easily be you. Sperm is usually more fluid.
when i went to the bathroom i saw plenty thick white in the toilet
No, you cannot tell from a smell if he ejaculated in you. You would know because some of the semen would eventually start to leak back out not long after intercourse. Maybe not a good idea to be sleeping with a man who isn't truthful, especially with things like this - that;s how you get unwanted or unplanned pregnancies or STDs.
I wouldn't say it smells like a condom at all when it happens, but it does have a unique smell. Still, if you didn't have any sperm dripping down your thighs, you have no conclusive proof he truly did. Hopefully he was wearing a condom and/or you're on birth control and have been for a while.