<human>: Throwaway since he uses reddit as well.

Last night I was looking through a drawer or my clothes at my boyfriends house and found a pair of black yoga type pants that were definitely not mine. My boyfriend was in the room so I asked him who's pants they were. He took them from me and said "I don't know, yours?" and I responded that they weren't mine. He then said they were probably the girl (28F) who his roommate (28m) recently broke up with.
He then started to say he found them (I think) but cut himself off. We didn't speak about it for the rest of the night but I had an uneasy feeling.

I dropped it for the time being but I couldn't help thinking, how would her pants end up in his room and in my drawer? Then this morning I woke up early to get ready and he got up fairly early as well. Usually he is still asleep when I leave. The first thing he did was move his backpack and the pants to the office. 

I thought this was very strange. He never gets up early and then to move the pants first thing?

Today at work he g-chatted me asking if everything was okay because I seemed a bit off. I responded I still felt weird about the pants and the fact he moved them this morning.

He replied:

"1) no idea where they came from, but yes my shit gets mixed in with roomates all the time

2) i moved my backpack and didn't realize they were on top, so they were in my office this morning

wasn't on purpose, i just got up on time for once. my backpack had my laptop so i just grabbed it when i woke up is all."

This also seemed weird, he accidentally moved them? But then again, would a girl really be able to leave without her pants?

He works from home all day in a different city than I do but we spend most nights together. Just not sure if this all ads up or not.

Can you summarize the given text in a few sentences?
<bot>: Found foreign pants in bf's room. He says he has no idea where they came from but might be his roommates' ex. All seems a little weird to me.