Peed while being fingered

The other day my boyfriend was fingering me and I peed myself without noticing. I don't know if it was because he made me completely lose control or whatever, (also I'd recently come off my period if that's relevant), but I didn't realise I needed to pee and then I did it in his bed. He said it was fine but I was so embarrassed and it's not the first time it's happened. I'm now really uncomfortable with him fingering me because I'm so scared it will happen again. I've been trying to tense up which helps a little bit but then I don't enjoy it as much. Can anyone help? I don't know why and I don't know how to stop it.