Talk to Urologist on Sexual Problem

I got married in dec 2019. all tests done, no issues with my wife or me. my semen analysis was ok too. the gynae has advised us to go for intercourse on alternate days after the period cycle ends. my problem is, due to work pressure or weakness, I don't feel like doing intercourse so often. like if I do it on Monday, I don't feel like doing it before Friday or Saturday. don't feel erection, even if I do foreplay. also, once I somehow achieve erection, then the intercourse goes fine and timing is also good. the only problem is starting. it takes me so much time to get arouse. I feel ashamed in front of my wife. I like her, love her, but am extremely ashamed in front of her. once or twice I went to washroom and watched porn and then for erection, immediately and started intercourse but I. can't follow this practice because watching porn is a sin and last time when I tried it, the guilt of commiting a sin was so strong that I lost erection again and had to dress up without interc