48 year old wife chasing her son's 20 year old best freind

i've been with my wife 26 years. we've been having problems for about 7-8 years. but within the last couple months things have hit rock bottom. i lost my job due to a disability and waiting for s.s. and she works part time. our house is in foreclousure. my wife in the last 3-4 months got emotionally close to our son's 20 year old best freind. my wife is 48 years old. the 20 year old feels creeped out about because its his best friends 48 year old mom. my wife keeps texting him and visiits him in his supermarket job. someone tell me if this is all right or not. i personally feel its sick and regardless of the age its very hurtfull to me. she denies any physical activity but i sense that there as been. someone please give me some input.