Is his cum normal?

Last night my boyfriend and I had sex. Normally we use condoms, but we unknowingly all out. We had already gotten things heated up and I decided to just let him pull out instead. After he came, I noticed his cum was extremely thick and mucusy looking. We've been dating for a few months now and I haven't really noticed this before, most likely because he always has had a condom on. All of my past sexual parters have had thinner, lighter cum. Is it normal for some guys to have a very very thick and sticky type of cum? Is it always going to be like that or does it change depending on various things?