Hurting like crazy

Lately I been noticing that my boyfriend has been standoffish he’s been leaving his house to spend the night at somebody house. Saturday night he spent the night at some lady house with his son which is 10 they both told me that it’s his cousin house and my gut I feel like his lying and he spent the night at somebody’s house yesterday he’s been acting so cold to me lately and I’m already going through depression because I miscarried our baby 2 months Ago. Can anybody give me some advice please. I’m just so hurt