What is the possibility? :/

Okay so back in March I had sex with my current bf, then we broke up and I was devastated so I went back to my ex and had sex with him :/ I just did it once with my ex for like 5 mins and he didn't finish inside me I told him to get off because I couldn't stand doing that. So I got my period in April and May on time as usual, then on May I had sex once with my current bf two days before O day.

Can there be a slight possibility that I got pregnant by my ex? I mean I got two normal periods after that.

Thanks!