You think he is cheating? Am I blind? 🙈😫

so been married for over 8 years, know my husband preaty well and so our sex life, this past two months sex have been weird, at weekends averything is same and perfect but if we have sex on thursdays, for example, after he came back from work, I have noticed he has a "new" difficulty to come and finished...and when this happen i've noticed he ejaculates so little amount of semen (almost nothing!! like he just empty himself somewhere else before).

so last weekend he went out to a bbq with his coworkers (just 4 hours and he came back home) we had sex that night and I noticed the same issue...he had trouble to finished "the job" (we even tried 3 positions and nothing) he lasted longer and when he FINALLY came he eyaculated almost nothing of semen 😪 ....I have to mention we did have sex that morning (like 11 hours prior the second time) many times we have had sex twice a day, morning and night without a problem and not the same amount of semen came out the second time but still is always a good amount since he had time to replenish those sperms (the whole day, you know)...the only thing that pops to my mind is that he just had sex with someone else right before having with me that night...it wasnt masturbation because we took a shower together that night...so, why he was so "empty". what would you think about it?...he hasnt been acting weird or different besides this but we havent had this kind of issue in the past...is like a part of me just knows this is not normal 🙄🤔 is he thinking I have no idea of whats going on or what the hell? He is so calm!! 🤷🏻‍♀️  I have to mention he is 38 years and im 34 but i dont think is aged related...we still young 🤷🏻‍♀️🙈