Suggest Cause And Remedy For White Thick Fluid Coming From The Penis

i am 44 years old. i have a new sex partner and we had unprotected sex for two weeks. we stopped having sex about 10 days ago and i have noticed a white thick fluid coming from my penis a couple of times during the day. I am also having a burning sensation while urinating and have a frequent need to urinate. this is the very first time that i had unprotected sex with a partner in two years. i was married before then. what caused this? what should i do to rectify this? i have also been drinking beer before going to bed very often during the last 3 weeks. i also gained weight.