marriage problems

Jo
How do you know when a marriage is over 
My husband was meeting up with a girl for months behind my back (apparently) just for coffee on a regular basis and I found out at the time I went mad but said ok and carried in now a few months down the line I don't think I love him anymore I think at the time I was scared of being on my own but now my head is clearer I keep thinking if it was just coffee why all the lies for months we have been together 15 1/2 years and have 2 children
I just don't know what to do my anxiety and depression have taken a turn for the worst and the doctor has upped my medication 
Just don't know what to do !!