I agree exactly with what mytoesrticklish said. This has been my experience.
Iam a guy who has the dual "interest", as I like to call it, of tickling, and female feet. For me, I had the foot interest first, and then the tickle interest came later. As far as arousal goes for me, it greatly helps me if Iam playing with and worshipping, (kissing feet, sucking on toes) the feet of the girl Iam involved sexually with. It greatly helps me in arousal. While I cant say that I never become aroused, and would never become aroused if I didnt play with the feet of the girl I was sexually intimate with, it could well become an obstacle in arousal for me if she forbade me to do so. I dont think anything is "concerning", unless it causes physical or emotional pain to either party in the relationship. If tickling you helps your boyfriend in becoming aroused sexually, and you are okay with that, then it is merely a matter of two people who are intimate and sexually involved, using a means with which to become aroused. If you are beginning to have thoughts of:" My gosh, this is bothering me that my boyfriend cant become aroused unless he tickles me and/ or plays with my feet, and this is making me uncomfortable, why is this happening?", it is at that point time to sit down and have an open discussion about your mutual sexual needs and wants. Discuss, negotiate, and try to set boundaries and compromise for what both you and he need in the relationship. That way, both of you can feel like your needs and wants are satisified. I'll use an example for myself.
While I do of course have the tickle interest,( I wouldnt be here if I didnt.) It is also important to me that I have foot worship as part of my sexual stimuli, to help me enjoy sex more. If I met someone who refused to ever let me play with her feet, I couldnt realistically stay with that person, because I would be deprived of something that has been important to me for a long time. If, however, I met someone who, say, didnt love the idea of having her feet paid attention to, because she was either too ticklish, or hated feet, what not, but she had all the other qualities, I could probably accept the idea of say, paying attention to her feet during some instances where we were making love, while being able to contain myself and not worship her feet at other times. This is what I mean by discussion, compromise, and resolution. I would say that for whatever your issues are with your boyfriend, discuss, compromise, both of you need to try and bend to make the other happy, and try to find a balance, for lack of a better word, where you can both feel as sexually, and emotionally satisfied as possible, Love is about compromise, and if you truly care for each other, things like this can be worked out, I believe for the good of the relationship.
Welcome to TMF. This is a great place, and, as you can see, we are all very supportive and open with one another about issues in our lives. Take care, and Good Luck.
Mitch