Whose Baby Is It? Need Help?

My husband and I had unprotected sex up until the 24th or 25th of last month. My period started on May 10th. I have a 28 day cycle. However, we separated for a short time. During this time, I had sex with someone else on the 29th of May. It wasn't protected, but he didn't get off. On the night of the 30th, I wiped and there was a clear and browin-ish colored glob on the paper. Is there any way that this child could be the other guy's and not my husband's child?