Remember the wedding night and Vansh's 8th vow "agar galti se mjhe dhoka dene ki galti kr betho to mjhe pta lagne se pehle khud ko khatam Kar Lena, or agar mene tumhe dhokha dia to m khud ko khatam kr lunga" these words were said very specifically so he is not going to betray her.
But.
The same night there was a scene when Vansh captured the spider and said "kitte bebkoof hote h na spiders, sabko dikha k jal bunte h, jaal esa buno ki kisiko dikhai na de warna shikari khud shikar ho jata h" Later that night before going to sleep he said "mere jaal dikhai nhi dete Ridhima"
So I guess, he is into something for sure but it won't be something that might harm her.