watery sperm

So i have a normal cycle for the most part... mainly about 28 days... ive never not gotten a period unless im pregnant... im in my early 30's and have 3 living kids.... a 14 yr old, an 11 year old and a 10 year old. ive been with my now partner 5 years and i miscarried a year and 8 months ago and have not been able to conceive again. i had never ever miscarried before. only 3 pregnancies before, all were successful as i mentioned i have 3 living kids. So im starting to think were gonna need professional help. i dont think im the issue as im very regular with my cycles, but i have noticed that his ejaculation contains some very watery sperm. and of course google has been all weirded out because if says it could mean low sperm count. He also has kids. 2. an 11 yr old and a 10 yr old. obviously we are both way older now then when we started having kids so maybe I could have an issue. who knows... im so lost in what to do now... also he has his daily dosage of 40's. (beer)... idk if thats whats causing the watery sperm... what do yall think.