Do you have a feelings your partner is seeing someone else? The first option is to ask your partner directly. If he/she keeps denying and you have this strong feelings that it’s happening, then you have a lot on your plate to deal with I think it’s very common for them to say no even when they are doing it, or someone is cheating on you behind your back, it’s simply because they don’t want you to, they to eat their cakes and still have it or because they just think of it as a filling, maybe they haven’t made up their minds to leave you yet. You should talk to this professional and reliable who once did a great job for me when I was going through such difficulties. CLOUDGEEKSYNC@GMAIL.COM