Checking up on flat mate

My partner is on holiday and owns his own place. His friend who he is also on holiday with lives with him too with his girlfriend (temporarily for a year and they're moving out in a few weeks)

My partner does most of the cleaning tidying around the flat and the other 2 don't often help or pull their weight.

He wants me to go to his place tomorrow morning to see if she's had a party there or had people stay over and is worried someone might have slept in his (our) bed.

I said if happily do it but please don't drag me into any unpleasantness if I tell you something has gone on.

I'm now having second thoughts, I'm just scared incase someone IS in his bed, or the place is a total mess etc

What what you do?

I would go. Make a note of the situation. Report back and let him sort it out.

I'm worried about the possible confrontation.
I was planning on going for a run then going back to his to shower and change etc before going home.
I'll be going early as I run at about 8am, what do I do if people are in his bed.

I'm really anxious about this

Well... if you're really worried... just don't go. Tell your partner you had second thoughts & decided it was something you just didn't feel comfortable doing. I agree with SadGirl, though. I think you could just stop by, take a quick look around, report back to your partner, & let him take it from there.

I would recommend not showering & changing at his place. And don't allow yourself to be dragged into the situation any further. From that standpoint, this becomes a matter of personal boundaries. Here are links to 3 articles, from PsychCentral's archives, on the subject of personal boundaries in relationships:

Why Healthy Relationships Always Have Boundaries & How to Set Boundaries in Yours

3 Ways to Develop and Maintain Healthy Relationship Boundaries

3 Steps to Setting Healthy Relationship Boundaries

I wouldn’t go.

First of all, they are leaving in a few weeks anyways.

But apart from that, this is his issue, I think it is over the line to expect you to determine if anyone slept in his bed or do his investigating for him. And if you report back and he creates a fuss, you are going to be involved in unpleasantness.

I wouldn’t go to other people’s places checking up on
anything. I’d stay out of it

If you are in a relationship and stay at his house frequently, I think it's a reasonable thing to ask of you. He is concerned and he trusts you...it's not like you are going to some random friend's house or something... He hasn't asked you to confront anyone or deal with the issue so I would do as the previous poster said. Check in and report back what you find...although the deed is done at this point or not done, I'm guessing based on the time.